/*
	Handlers for ti99 disk images

	We support the following types of image:
	* floppy disks ("DSK format") in v9t9, pc99 and old mess image format
	* hard disks ("WIN format") in MAME harddisk format (256-byte sectors only,
	  i.e. no SCSI)
	Files are extracted in TIFILES format.  There is a compile-time option to
	extract text files in flat format instead, but I need to re-implement it
	properly (using filters comes to mind).

	Raphael Nabet, 2002-2004

	TODO:
	- finish and test hd support ***test sibling FDR support***
	- check allocation bitmap against corruption when an image is opened
*/

#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <assert.h>
#include "osdepend.h"
#include "imgtoolx.h"
#include "harddisk.h"
#include "imghd.h"

/*
	Concepts shared by both disk structures:
	----------------------------------------

	In both formats, the entire disk surface is split into physical records,
	each 256-byte-long.  For best efficiency, the sector size is usually 256
	bytes so that one sector is equivalent to a physical record (this is true
	with floppies and HFDC hard disks).  If the sector size is not 256 bytes
	(e.g. 512 bytes with SCSI hard disks, possibly 128 bytes on a TI-99
	simulator running on TI-990), sectors are grouped or split to form 256-byte
	physical records.  Physical records are numbered from 0, with the first
	starting on sector 0 track 0.  To avoid confusion with physical records in
	files, such physical records will be called "absolute physical records",
	abbreviated as "absolute physrecs" or "aphysrecs".

	Disk space is allocated in units referred to as AUs.  Each AU represents an
	integral number of 256-byte physical records.  The number of physrecs per
	AU varies depending on the disk format and size.  AUs are numbered from 0,
	with the first starting with absolute physrec 0.

	Absolute physrec 0 contains a 256-byte record with volume information,
	which is called "Volume Information Block", abbreviated as "vib".

	To keep track of which areas on the disk are allocated and which are free,
	disk managers maintain a bit map of allocated AUs (called "allocation
	bitmap", abbreviated as "abm").  Each bit in the allocation bitmap
	represents an AU: if a bit is 0, the AU is free; if a bit is 1, the AU is
	allocated (or possibly bad if the disk manager can track bad sectors).
	Where on the disk the abm is located depends on the disk structure (see
	structure-specific description for details).

	Files are implemented as a succession of 256-byte physical records.  To
	avoid confusion with absolute physical records, these physical records will
	be called "file physical records", abbreviated as "file physrecs" or
	"fphysrecs".

	Programs do normally not access file physical records directly.  They may
	call high-level file routines that enable to create either fixed-lenght
	logical records of any size from 1 through 255, or variable-lenght records
	of any size from 0 through 254: logical records are grouped by file
	managers into 256-byte physical records.  Some disk managers (HFDC and
	SCSI) allow programs to create fixed-lenght records larger than 255 bytes,
	too, but few programs use this possibility.  Additionally, program files
	can be created: program files do not implement any logical record, and can
	be seen as a flat byte stream, not unlike files under MSDOS, UNIX and the C
	standard library.  (Unfortunately, the API for program files lacks
	flexibility, and most programs that need to process a flat byte stream
	will use fixed-size records of 128 bytes.)

		Fixed-length records (reclen < 256) are grouped like this:
			  fphysrec 0        fphysrec 1
			_______________   _______________
			|R0 |R1 |R2 |X|   |R3 |R4 |R5 |X|
			---------------   ---------------
			            \_/               \_/
			           unused            unused
			      (size < reclen)   (size < reclen)

		Fixed-length records (reclen > 256) are grouped like this:
			  fphysrec 0         fphysrec 1         fphysrec 2          fphysrec 3      ...
			_________________  _________________  _________________   _________________
			|  R0 (#0-255)  |  | R0 (#256-511) |  |R0 (#512-end)|X|   |  R1 (#0-255)  |   ...
			-----------------  -----------------  -----------------   -----------------
			                                                    \_/
			                                                   unused

		Variable lenght records are grouped like this:
			                 fphysrec 0:
			byte:
			        ------------------------------
			      0 |l0 = lenght of record 0 data|
			        |----------------------------|
			      1 |                            |
			        |                            |
			      : |       record 0 data        |
			        |                            |
			     l0 |                            |
			        |----------------------------|
			   l0+1 |l1 = lenght of record 1 data|
			        |----------------------------|
			   l0+2 |                            |
			        |                            |
			      : |       record 1 data        |
			        |                            |
			l0+l1+1 |                            |
			        |----------------------------|
			      : :                            :
			      : :                            :
			        |----------------------------|
			      n |lm = lenght of record m data|
			        |----------------------------|
			    n+1 |                            |
			        |                            |
			      : |       record m data        |
			        |                            |
			   n+lm |                            |
			        |----------------------------|
			 n+lm+1 |>ff: EOR mark               |
			        |----------------------------|
			 n+lm+2 |                            |
			        |                            |
			      : |           unused           |
			      : |(we should have size < lm+1)|
			        |                            |
			    255 |                            |
			        ------------------------------

			                 fphysrec 1:
			byte:
			        ------------------------------
			      0 |lm+1=lenght of record 0 data|
			        |----------------------------|
			      1 |                            |
			        |                            |
			      : |      record m+1 data       |
			        |                            |
			   lm+1 |                            |
			        |----------------------------|
			      : :                            :
			      : :                            :

			I think the EOR mark is not required if all 256 bytes of a physical
			record are used by logical records.


	All files are associated with a "file descriptor record" ("fdr") that holds
	file information (name, format, length) and points to the data AUs. The WIN
	disk structure also supports sibling FDRs, in case a file is so fragmented
	that all the data pointers cannot fit in one FDR; the DSK disk structure
	does not implement any such feature, and you may be unable to append data
	to an existing file if it is too fragmented, even though the disk is not
	full.


	DSK disk structure:
	-------------------

	The DSK disk structure is used for floppy disks, and a few RAMDISKs as
	well.  It supports 1600 AUs and 16 MBytes at most (the 16 MByte value is a
	theorical maximum, as I doubt anyone has ever created so big a DSK volume).

	The disk sector size is always 256 bytes (the only potential exceptions are
	the SCSI floppy disk units and the TI-99 simulator on TI-990, but I don't
	know anything about either).

	For some reason, the number of physrecs per AU is always a power of 2.
	Originally, AUs always were one physical record each.  However, since the
	allocation bitmap cannot support more than 1600 AUs, disks larger than
	400kbytes need to have several physical records per AU.  Note that
	relatively few disk controllers implement AUs that span multiple physical
	records (IIRC, these are Myarc's HFDC, SCSI DSR with floppy disk interface,
	and some upgraded Myarc and Corcomp DD floppy controllers).

	The allocation bitmap is located in the VIB.  It is 200 bytes long, and
	supports 1600 AUs at most.

	Directories are implemented with a "File Descriptor Index Record" (FDIR)
	for each directory.  The FDIR is array of 0 through 128 words, containing
	the aphysrec address of each fdr in the directory, sorted by ascending file
	name, terminated with a 0.  Note that, while we should be prepared to read
	images images with 128 entries, I think (not 100% sure) that we should
	write no more than 127 for compatibility with some existing disk managers.

	Originally, the DSK structure only supported one directory level (i.e. the
	root directory level).  The FDIR record for the root directory is always
	located in aphysrec 1.  Moreover, Myarc extended the DSK structure to
	support up to 3 subdirectories in the root directory (note that there is no
	support for more subdirs, or for subdirs located in subdirs).  To do so,
	they used an unused field of the VIB to hold the 10-char name of each
	directory and the aphysrec address of the associated FDIR record.

	aphysrec 0: Volume Information Block (VIB): see below
	aphysrec 1: FDIR for root directory
	Remaining AUs are used for fdr and data (and subdirectory FDIR if
	applicable).  There is one FDIR record per directory; the FDIR points to
	the FDR for each file in the directory.  The FDR (File Descriptor Record)
	contains the file information (name, format, lenght, pointers to data
	physrecs/AUs, etc).


	WIN disk structure:
	-------------------

	The WIN disk structure is used for hard disks.  It supports 65535 AUs and
	256 MBytes at most.

	The disk sector size is 256 bytes on HFDC, 512 bytes on SCSI.  512-byte
	sectors are split into 256-byte physical records.

	We may have from 1 through 16 physrecs per AUs.  Since we cannot have more
	than 65535 AUs, we need to have several physical records per AU in disks
	larger than 16 Mbytes.

	Contrary to the DSK disk structure, the WIN disk structure supports
	hierarchic subdirectories, with a limit of 114 subdirectories and 127 files
	per directory.  Each directory is associated with both a "Directory
	Descriptor Record" (DDR) and a "File Descriptor Index Record" (FDIR).  The
	only exception is the root directory, which uses the VIB instead of a DDR
	(the VIB includes all the important fields of the DDR).  The DDR contains
	some directory info (name, number of files and subdirectories directly
	enclosed in the directory, AU address of the FDIR of the parent directory,
	etc), the AU address of the associated FDIR, and the AU address of the DDR
	of up to 114 subdirectories, sorted by ascending directory name.  The WIN
	FDIR is similar to, yet different from, the DSK FDIR: it contains up to 127
	(vs. 128) AU address (vs. aphysrec address) of each fdr in the directory,
	sorted by ascending file name.  Additionally, it includes the AU address of
	the associated DDR.

	When a file has more than 54 data fragments, the disk manager creates
	sibling FDRs that hold additional fragments.  (Sibling FDRs are called
	offspring FDRs in most existing documentation, but I prefer "sibling FDRs"
	as "offspring FDRs" wrongly suggests a directory-like hierarchy.
	Incidentally, I cannot really figure out why they chose to duplicate the
	FDR rather than create a file extension record, but there must be a
	reason.)  Note that sibling FDRs usually fill unused physrecs in the AU
	allocated for the eldest FDR, and a new AU is allocated for new sibling
	FDRs only when the first AU is full.

	aphysrec 0: Volume Information Block (VIB): see below
	aphysrec 1-n (where n = 1+SUP(number_of_AUs/2048)): Volume bitmap
	Remaining AUs are used for ddr, fdir, fdr and data.
*/

/* Since string length is encoded with a byte, the maximum length of a string
is 255.  Since we need to add a device name (1 char minimum, typically 4 chars)
and a '.' separator, we chose a practical value of 250 (though few applications
will accept paths of such lenght). */
#define MAX_PATH_LEN 253
#define MAX_SAFE_PATH_LEN 250

#define MAX_DIR_LEVEL 125	/* We need to put a recursion limit to avoid endless recursion hazard */


#if 0
#pragma mark MISCELLANEOUS UTILITIES
#endif

/*
	Miscellaneous utilities that are used to handle TI data types
*/

typedef struct UINT16BE
{
	UINT8 bytes[2];
} UINT16BE;

typedef struct UINT16LE
{
	UINT8 bytes[2];
} UINT16LE;

INLINE UINT16 get_UINT16BE(UINT16BE word)
{
	return (word.bytes[0] << 8) | word.bytes[1];
}

INLINE void set_UINT16BE(UINT16BE *word, UINT16 data)
{
	word->bytes[0] = (data >> 8) & 0xff;
	word->bytes[1] = data & 0xff;
}

INLINE UINT16 get_UINT16LE(UINT16LE word)
{
	return word.bytes[0] | (word.bytes[1] << 8);
}

INLINE void set_UINT16LE(UINT16LE *word, UINT16 data)
{
	word->bytes[0] = data & 0xff;
	word->bytes[1] = (data >> 8) & 0xff;
}

/*
	Convert a C string to a 10-character file name (padded with spaces if necessary)

	dst (O): destination 10-character array
	src (I): source C string
*/
static void str_to_fname(char dst[10], const char *src)
{
	int i;


	i = 0;

	/* copy 10 characters at most */
	if (src)
		while ((i<10) && (src[i]!='\0'))
		{
			dst[i] = src[i];
			i++;
		}

	/* pad with spaces */
	while (i<10)
	{
		dst[i] = ' ';
		i++;
	}
}

/*
	Convert a 10-character file name to a C string (removing trailing spaces if necessary)

	dst (O): destination C string
	src (I): source 10-character array
	n (I): lenght of dst buffer (string may be truncated if less than 11)
*/
static void fname_to_str(char *dst, const char src[10], int n)
{
	int i;
	int last_nonspace;


	/* copy 10 characters at most */
	if (--n > 10)
		n = 10;

	/* copy filename */
	i = 0;
	last_nonspace = -1;

	while (i<n)
	{
		dst[i] = src[i];
		if (src[i] != ' ')
			last_nonspace = i;
		i++;
	}

	/* terminate with '\0' */
	dst[last_nonspace+1] = '\0';
}

/*
	Check a 10-character file name.

	filename (I): 10-character array with file name

	Return non-zero if the file name is invalid.
*/
static int check_fname(const char filename[10])
{
	int i;
	int space_found_flag;


	/* check and copy file name */
	space_found_flag = FALSE;
	for (i=0; i<10; i++)
	{
		switch (filename[i])
		{
		case '.':
		case '\0':
			/* illegal characters */
			return 1;
		case ' ':
			/* illegal in a file name, but file names shorter than 10
			characters are padded with spaces */
			space_found_flag = TRUE;
			break;
		default:
			/* all other characters are legal (though non-ASCII characters,
			control characters and even lower-case characters are not
			recommended) */
			if (space_found_flag)
				return 1;
			break;
		}
	}

	return 0;
}

/*
	Check a file path.

	fpath (I): C string with file path

	Return non-zero if the file path is invalid.
*/
static int check_fpath(const char *fpath)
{
	const char *element_start, *element_end;
	int element_len;


	/* first check that the path is not too long and that there is no space
	character */
	if ((strlen(fpath) > MAX_PATH_LEN) || strchr(fpath, ' '))
		return 1;

	/* check that each path element has an acceptable lenght */
	element_start = fpath;
	do
	{
		/* find next path element */
		element_end = strchr(element_start, '.');
		element_len = element_end ? (element_end - element_start) : strlen(element_start);
		if ((element_len > 10) || (element_len == 0))
			return 1;

		/* iterate */
		if (element_end)
			element_start = element_end+1;
		else
			element_start = NULL;
	}
	while (element_start);

	return 0;
}

#if 0
#pragma mark -
#pragma mark LEVEL 1 DISK ROUTINES
#endif

/*
	Level 1 deals with accessing the disk hardware (in our case, the raw disk
	image).

	Higher level routines will only know the disk as a succession of
	256-byte-long physical records addressed by a linear address.
*/

/*
	Disk geometry
*/
typedef struct ti99_geometry
{
	int secspertrack;
	int cylinders;
	int heads;
} ti99_geometry;

/*
	Physical sector address
*/
typedef struct ti99_sector_address
{
	int sector;
	int cylinder;
	int side;
} ti99_sector_address;

/*
	Time stamp (used in fdr, and WIN VIB/DDR)
*/
typedef struct ti99_date_time
{
	UINT8 time_MSB, time_LSB;/* 0-4: hour, 5-10: minutes, 11-15: seconds/2 */
	UINT8 date_MSB, date_LSB;/* 0-6: year, 7-10: month, 11-15: day */
} ti99_date_time;

/*
	Subdirectory descriptor (HFDC only)

	The HFDC supports up to 3 subdirectories.
*/
typedef struct dsk_subdir
{
	char name[10];			/* subdirectory name (10 characters, pad with spaces) */
	UINT16BE fdir_aphysrec;	/* aphysrec address of fdir record for this subdirectory */
} dsk_subdir;

/*
	DSK VIB record

	Most fields in this record are only revelant to level 2 routines, but level
	1 routines need the disk geometry information extracted from the VIB.
*/
typedef struct dsk_vib
{
	char name[10];			/* disk volume name (10 characters, pad with spaces) */
	UINT16BE totphysrecs;	/* total number of physrecs on disk (usually 360, */
								/* 720, 640, 1280 or 1440).  (TI originally */
								/* said it should be the total number of AUs, */
								/* but, in practice, DSRs that supports disks */
								/* over 400kbytes (e.g. HFDC) write the total */
								/* number of physrecs.) */
	UINT8 secspertrack;		/* sectors per track (usually 9 (FM SD), */
								/* 16 or 18 (MFM DD), or 36 (MFM HD) */
	UINT8 id[3];			/* 'DSK' */
	UINT8 protection;		/* 'P' if disk is protected, ' ' otherwise. */
	UINT8 cylinders;		/* tracks per side (usually 40) */
	UINT8 heads;			/* sides (1 or 2) */
	UINT8 density;			/* density: 1 (FM SD), 2 (MFM DD), or 3 (MFM HD) */
	dsk_subdir subdir[3];	/* descriptor for up to 3 subdirectories (HFDC only) */
								/* reserved by TI */
	UINT8 abm[200];			/* allocation bitmap: there is one bit per AU. */
								/* A binary 1 in a bit position indicates that */
								/* the allocation unit associated with that */
								/* bit has been allocated. */
								/* Bits corresponding to system reserved AUs, */
								/* non-existant AUs, and bad AUs, are set to one, too. */
								/* (AU 0 is associated to LSBit of byte 0, */
								/* AU 7 to MSBit of byte 0, AU 8 to LSBit */
								/* of byte 1, etc.) */
} dsk_vib;

typedef enum
{
	if_mess,
	if_v9t9,
	if_pc99_fm,
	if_pc99_mfm,
	if_harddisk
} ti99_img_format;

/*
	level-1 disk image descriptor
*/
typedef struct ti99_lvl1_imgref
{
	ti99_img_format img_format;	/* tells the image format */
	imgtool_stream *file_handle;		/* imgtool file handle */
	struct mess_hard_disk_file harddisk_handle;		/* MAME harddisk handle (harddisk format) */
	ti99_geometry geometry;		/* geometry */
	unsigned pc99_track_len;		/* unformatted track lenght (pc99 format) */
	UINT32 *pc99_data_offset_array;	/* offset for each sector (pc99 format) */
} ti99_lvl1_imgref;

/*
	calculate CRC for data address marks or sector data

	crc (I/O): current CRC value to be updated (initialize to 0xffff before
		calling this function for the first time)
	value: new byte of data to update the CRC with
*/
static void calc_crc(UINT16 *crc, UINT8 value)
{
	UINT8 l, h;

	l = value ^ (*crc >> 8);
	*crc = (*crc & 0xff) | (l << 8);
	l >>= 4;
	l ^= (*crc >> 8);
	*crc <<= 8;
	*crc = (*crc & 0xff00) | l;
	l = (l << 4) | (l >> 4);
	h = l;
	l = (l << 2) | (l >> 6);
	l &= 0x1f;
	*crc = *crc ^ (l << 8);
	l = h & 0xf0;
	*crc = *crc ^ (l << 8);
	l = (h << 1) | (h >> 7);
	l &= 0xe0;
	*crc = *crc ^ l;
}

/*
	Parse a PC99 disk image

	file_handle (I/O): imgtool file handle
	fm_format (I): if true, the image is in FM format, otherwise it is in MFM
		format
	pass (I): 0 for first pass, 1 for second pass
	vib (O): buffer where the vib should be stored (first pass)
	geometry (O): disk image geometry (second pass)
	data_offset_array (O): array of data offset to generate (second pass)
	out_track_len (O): track lenght is returned there

	Return imgtool error code
*/
#define MAX_TRACK_LEN 6872
#define DATA_OFFSET_NONE 0xffffffff
static int parse_pc99_image(imgtool_stream *file_handle, int fm_format, int pass, dsk_vib *vib, const ti99_geometry *geometry, UINT32 *data_offset_array, unsigned *out_track_len)
{
	int track_len, num_tracks;	/* lenght of a track in bytes, and number of tracks */
	int phys_track;
	int expected_cylinder, expected_head;
	int track_start_pos, track_pos;
	UINT8 c;
	UINT8 cylinder, head, sector;
	int seclen;
	UINT8 crc1, crc2;
	UINT16 crc;
	long data_offset;
	UINT8 track_buf[MAX_TRACK_LEN];
	int i;

	if (fm_format)
		track_len = 3253;
	else
		track_len = 6872;

	if (out_track_len)
		*out_track_len = track_len;

	if (stream_size(file_handle) % track_len)
		return IMGTOOLERR_CORRUPTIMAGE;

	num_tracks = stream_size(file_handle) / track_len;
	if (num_tracks <= 0)
		return IMGTOOLERR_CORRUPTIMAGE;

	/* we only support 40-track-per-side images */
	if ((num_tracks != 40) && (num_tracks != 80))
		return IMGTOOLERR_UNIMPLEMENTED;

	if (pass == 1)
	{
		/* initialize offset map */
		for (head = 0; head < geometry->heads; head++)
			for (cylinder = 0; cylinder < geometry->cylinders; cylinder++)
				for (sector = 0; sector < geometry->secspertrack; sector++)
					data_offset_array[(head*geometry->cylinders + cylinder)*geometry->secspertrack + sector] = DATA_OFFSET_NONE;
	}
	/* rewind to start of file */
	stream_seek(file_handle, 0, SEEK_SET);

	/* pass 0 only looks for vib in track 0; pass 1 scans every track */
	for (phys_track=0; phys_track < ((pass == 1) ? num_tracks : 1); phys_track++)
	{
		if (stream_read(file_handle, track_buf, track_len) != track_len)
			return IMGTOOLERR_READERROR;

		/* we only support 40-track-per-side images */
		expected_cylinder = phys_track % 40;
		expected_head = phys_track / 40;

		track_start_pos = 0;

		while (track_start_pos < track_len)
		{
			if (fm_format)
			{
				do
				{
					c = track_buf[track_start_pos];
					track_start_pos++;
				} while ((c != 0xfe) && (track_start_pos < track_len));

				if (c != 0xfe)
					break;

				track_pos = track_start_pos;

				crc = 0xffff;
				calc_crc(& crc, c);
			}
			else
			{
				do
				{
					c = track_buf[track_start_pos];
					track_start_pos++;
				} while ((c != 0xa1) && (track_start_pos < track_len));

				if (c != 0xa1)
					break;

				track_pos = track_start_pos;

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xa1)
					continue;

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xa1)
					continue;

				crc = 0xffff;
				calc_crc(& crc, c);

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xfe)
					continue;
			}

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			cylinder = c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			head = c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			sector = c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			seclen = 128 << c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			crc1 = c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			crc2 = c;
			calc_crc(& crc, c);

			/* CRC seems to be completely hosed */
			/*if (crc)
				printf("aargh!");*/
			if ((seclen != 256) || (crc1 != 0xf7) || (crc2 != 0xf7)
					|| (cylinder != expected_cylinder) || (head != expected_head)
					|| ((pass == 1) && ((cylinder >= geometry->cylinders)
										|| (head >= geometry->heads)
										|| (sector >= geometry->secspertrack))))
				continue;

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			while (c == (fm_format ? 0xff : 0x4e))
			{
				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;
			}

			while (c == 0x00)
			{
				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;
			}

			if (fm_format)
			{
				if (c != 0xfb)
					continue;

				crc = 0xffff;
				calc_crc(& crc, c);
			}
			else
			{
				if (c != 0xa1)
					continue;

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xa1)
					continue;

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xa1)
					continue;

				crc = 0xffff;
				calc_crc(& crc, c);

				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				if (c != 0xfb)
					continue;
			}
			data_offset = track_pos;
			for (i=0; i<seclen; i++)
			{
				c = track_buf[track_pos];
				track_pos++;
				if (track_pos == track_len)
					track_pos = 0;

				calc_crc(& crc, c);
			}

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			crc1 = c;
			calc_crc(& crc, c);

			c = track_buf[track_pos];
			track_pos++;
			if (track_pos == track_len)
				track_pos = 0;

			crc2 = c;
			calc_crc(& crc, c);

			/* CRC seems to be completely hosed */
			/*if (crc)
				printf("aargh!");*/
			if ((crc1 != 0xf7) || (crc2 != 0xf7))
				continue;

			switch (pass)
			{
			case 0:
				if ((cylinder == 0) && (head == 0) && (sector == 0))
				{
					/* return vib */
					if ((data_offset + 256) <= track_len)
						memcpy(vib, track_buf + data_offset, 256);
					else
					{
						memcpy((UINT8 *)vib, track_buf + data_offset, track_len-data_offset);
						memcpy((UINT8 *)vib + (track_len-data_offset), track_buf, 256-(track_len-data_offset));
					}
					return 0;
				}
				break;

			case 1:
				/* set up offset map */
				if (data_offset_array[(head*geometry->cylinders + cylinder)*geometry->secspertrack + sector] != DATA_OFFSET_NONE)
					/* error: duplicate sector */
					return IMGTOOLERR_CORRUPTIMAGE;
				data_offset_array[(head*geometry->cylinders + cylinder)*geometry->secspertrack + sector] = data_offset;
				break;
			}
		}
	}

	if (pass == 0)
		return IMGTOOLERR_CORRUPTIMAGE;

	if (pass == 1)
	{
		/* check offset map */
		for (head = 0; head < geometry->heads; head++)
			for (cylinder = 0; cylinder < geometry->cylinders; cylinder++)
				for (sector = 0; sector < geometry->secspertrack; sector++)
					if (data_offset_array[(head*geometry->cylinders + cylinder)*geometry->secspertrack + sector] == DATA_OFFSET_NONE)
						/* error: missing sector */
						return IMGTOOLERR_CORRUPTIMAGE;
	}

	return 0;
}


/*
	Read the volume information block (aphysrec 0) assuming no geometry
	information.  (Called when an image is opened to figure out the
	geometry information.)

	file_handle (I/O): imgtool file handle
	img_format (I): image format (MESS, V9T9 or PC99)
	dest (O): pointer to 256-byte destination buffer

	Return imgtool error code
*/
static int read_image_vib_no_geometry(imgtool_stream *file_handle, ti99_img_format img_format, dsk_vib *dest)
{
	int reply;

	switch (img_format)
	{
	case if_mess:
	case if_v9t9:
		/* seek to sector */
		reply = stream_seek(file_handle, 0, SEEK_SET);
		if (reply)
			return IMGTOOLERR_READERROR;
		/* read it */
		reply = stream_read(file_handle, dest, 256);
		if (reply != 256)
			return IMGTOOLERR_READERROR;
		return 0;

	case if_pc99_fm:
	case if_pc99_mfm:
		return parse_pc99_image(file_handle, img_format == if_pc99_fm, 0, dest, NULL, NULL, NULL);

	case if_harddisk:
		/* not implemented, because we don't need it */
		break;
	}

	return IMGTOOLERR_UNIMPLEMENTED;
}

/*
	Open a disk image at level 1

	file_handle (I/O): imgtool file handle
	img_format (I): image format (MESS, V9T9, PC99, or MAME harddisk)
	l1_img (O): level-1 image handle
	vib (O): buffer where the vib should be stored (floppy images only)

	Return imgtool error code
*/
static imgtoolerr_t open_image_lvl1(imgtool_stream *file_handle, ti99_img_format img_format, ti99_lvl1_imgref *l1_img, dsk_vib *vib)
{
	imgtoolerr_t err;
	int reply;
	int totphysrecs;


	l1_img->img_format = img_format;
	l1_img->file_handle = file_handle;

	if (img_format == if_harddisk)
	{
		const hard_disk_info *info; 

		err = imghd_open(file_handle, &l1_img->harddisk_handle);
		if (err)
			return err;

		info = imghd_get_header(&l1_img->harddisk_handle);
		l1_img->geometry.cylinders = info->cylinders;
		l1_img->geometry.heads = info->heads;
		l1_img->geometry.secspertrack = info->sectors;
		if (info->sectorbytes != 256)
		{
			imghd_close(&l1_img->harddisk_handle);
			return IMGTOOLERR_CORRUPTIMAGE;	/* TODO: support 512-byte sectors */
		}

		/* read vib */
		/*reply = read_absolute_physrec(l1_img, 0, vib);
		if (reply)
			return reply;*/
	}
	else
	{
		/* read vib */
		reply = read_image_vib_no_geometry(file_handle, img_format, vib);
		if (reply)
			return reply;

		/* extract geometry information */
		totphysrecs = get_UINT16BE(vib->totphysrecs);

		l1_img->geometry.secspertrack = vib->secspertrack;
		if (l1_img->geometry.secspertrack == 0)
			/* Some images might be like this, because the original SSSD TI
			controller always assumes 9. */
			l1_img->geometry.secspertrack = 9;
		l1_img->geometry.cylinders = vib->cylinders;
		if (l1_img->geometry.cylinders == 0)
			/* Some images are like this, because the original SSSD TI
			controller always assumes 40. */
			l1_img->geometry.cylinders = 40;
		l1_img->geometry.heads = vib->heads;
		if (l1_img->geometry.heads == 0)
			/* Some images are like this, because the original SSSD TI
			controller always assumes that tracks beyond 40 are on side 2. */
			l1_img->geometry.heads = totphysrecs / (l1_img->geometry.secspertrack * l1_img->geometry.cylinders);

		/* check information */
		if ((totphysrecs != (l1_img->geometry.secspertrack * l1_img->geometry.cylinders * l1_img->geometry.heads))
				|| (totphysrecs < 2)
				|| memcmp(vib->id, "DSK", 3) || (! strchr(" P", vib->id[3]))
				|| (((img_format == if_mess) || (img_format == if_v9t9))
					&& (stream_size(file_handle) != totphysrecs*256)))
			return IMGTOOLERR_CORRUPTIMAGE;

		if ((img_format == if_pc99_fm) || (img_format == if_pc99_mfm))
		{
			l1_img->pc99_data_offset_array = malloc(sizeof(*l1_img->pc99_data_offset_array)*totphysrecs);
			if (! l1_img->pc99_data_offset_array)
				return IMGTOOLERR_OUTOFMEMORY;
			reply = parse_pc99_image(file_handle, img_format == if_pc99_fm, 1, NULL, & l1_img->geometry, l1_img->pc99_data_offset_array, &l1_img->pc99_track_len);
			if (reply)
			{
				free(l1_img->pc99_data_offset_array);
				return reply;
			}
		}
	}

	return 0;
}

/*
	Close a disk image at level 1

	l1_img (I/O): level-1 image handle

	Return imgtool error code
*/
static void close_image_lvl1(ti99_lvl1_imgref *l1_img)
{
	if (l1_img->img_format == if_harddisk)
	{
		imghd_close(&l1_img->harddisk_handle);
	}

	stream_close(l1_img->file_handle);

	if ((l1_img->img_format == if_pc99_fm) || (l1_img->img_format == if_pc99_mfm))
		free(l1_img->pc99_data_offset_array);
}

/*
	Convert physical sector address to offset in disk image (old MESS and V9T9
	formats only)

	l1_img (I/O): level-1 image handle
	address (I): physical sector address

	Return offset in image
*/
INLINE int sector_address_to_image_offset(const ti99_lvl1_imgref *l1_img, const ti99_sector_address *address)
{
	int offset = 0;

	switch (l1_img->img_format)
	{
	case if_mess:
		/* old MESS format */
		offset = (((address->cylinder*l1_img->geometry.heads) + address->side)*l1_img->geometry.secspertrack + address->sector)*256;
		break;

	case if_v9t9:
		/* V9T9 format */
		if (address->side & 1)
			/* on side 1, tracks are stored in the reverse order */
			offset = (((address->side*l1_img->geometry.cylinders) + (l1_img->geometry.cylinders-1 - address->cylinder))*l1_img->geometry.secspertrack + address->sector)*256;
		else
			offset = (((address->side*l1_img->geometry.cylinders) + address->cylinder)*l1_img->geometry.secspertrack + address->sector)*256;
		break;

	case if_pc99_fm:
	case if_pc99_mfm:
		/* pc99 format */
	case if_harddisk:
		/* harddisk format */
		assert(1);		/* not implemented */
		break;
	}

	return offset;
}

/*
	Read one 256-byte sector from a disk image

	l1_img (I/O): level-1 image handle
	address (I): physical sector address
	dest (O): pointer to 256-byte destination buffer

	Return non-zero on error
*/
static int read_sector(ti99_lvl1_imgref *l1_img, const ti99_sector_address *address, void *dest)
{
	int reply;
	UINT32 track_len, track_offset, sector_offset;

	switch (l1_img->img_format)
	{
	case if_mess:
		/* old MESS format */
	case if_v9t9:
		/* V9T9 format */
		/* seek to sector */
		reply = stream_seek(l1_img->file_handle, sector_address_to_image_offset(l1_img, address), SEEK_SET);
		if (reply)
			return 1;
		/* read it */
		reply = stream_read(l1_img->file_handle, dest, 256);
		if (reply != 256)
			return 1;
		break;

	case if_pc99_fm:
	case if_pc99_mfm:
		/* pc99 format */
		track_len = l1_img->pc99_track_len;
		track_offset = (address->side*l1_img->geometry.cylinders + address->cylinder)*track_len;
		sector_offset = l1_img->pc99_data_offset_array[(address->side*l1_img->geometry.cylinders + address->cylinder)*l1_img->geometry.secspertrack + address->sector];

		if ((sector_offset + 256) <= track_len)
		{
			/* seek to sector */
			reply = stream_seek(l1_img->file_handle, track_offset+sector_offset, SEEK_SET);
			if (reply)
				return 1;
			/* read it */
			reply = stream_read(l1_img->file_handle, dest, 256);
			if (reply != 256)
				return 1;
		}
		else
		{
			/* seek to sector */
			reply = stream_seek(l1_img->file_handle, track_offset+sector_offset, SEEK_SET);
			if (reply)
				return 1;
			/* read first chunk (until end of track) */
			reply = stream_read(l1_img->file_handle, (UINT8 *)dest, track_len-sector_offset);
			if (reply != track_len-sector_offset)
				return 1;

			/* wrap to start of track */
			reply = stream_seek(l1_img->file_handle, track_offset, SEEK_SET);
			if (reply)
				return 1;
			/* read remnant of sector */
			reply = stream_read(l1_img->file_handle, (UINT8 *)dest + (track_len-sector_offset), 256-(track_len-sector_offset));
			if (reply != 256-(track_len-sector_offset))
				return 1;
		}
		break;

	case if_harddisk:
		/* not implemented */
		assert(1);
		/*return imghd_read(l1_img->harddisk_handle, ((address->cylinder*l1_img->geometry.heads) + address->side)*l1_img->geometry.secspertrack + address->sector, 1, dest) != 1;*/
		break;
	}

	return 0;
}

/*
	Write one 256-byte sector to a disk image

	l1_img (I/O): level-1 image handle
	address (I): physical sector address
	src (I): pointer to 256-byte source buffer

	Return non-zero on error
*/
static int write_sector(ti99_lvl1_imgref *l1_img, const ti99_sector_address *address, const void *src)
{
	int reply;
	UINT32 track_len, track_offset, sector_offset;

	switch (l1_img->img_format)
	{
	case if_mess:
		/* old MESS format */
	case if_v9t9:
		/* V9T9 format */
		/* seek to sector */
		reply = stream_seek(l1_img->file_handle, sector_address_to_image_offset(l1_img, address), SEEK_SET);
		if (reply)
			return 1;
		/* write it */
		reply = stream_write(l1_img->file_handle, src, 256);
		if (reply != 256)
			return 1;
		break;

	case if_pc99_fm:
	case if_pc99_mfm:
		/* pc99 format */
		track_len = l1_img->pc99_track_len;
		track_offset = (address->side*l1_img->geometry.cylinders + address->cylinder)*track_len;
		sector_offset = l1_img->pc99_data_offset_array[(address->side*l1_img->geometry.cylinders + address->cylinder)*l1_img->geometry.secspertrack + address->sector];

		if ((sector_offset + 256) <= track_len)
		{
			/* seek to sector */
			reply = stream_seek(l1_img->file_handle, track_offset+sector_offset, SEEK_SET);
			if (reply)
				return 1;
			/* write it */
			reply = stream_write(l1_img->file_handle, src, 256);
			if (reply != 256)
				return 1;
		}
		else
		{
			/* seek to sector */
			reply = stream_seek(l1_img->file_handle, track_offset+sector_offset, SEEK_SET);
			if (reply)
				return 1;
			/* write first chunk (until end of track) */
			reply = stream_write(l1_img->file_handle, (UINT8 *)src, track_len-sector_offset);
			if (reply != track_len-sector_offset)
				return 1;

			/* wrap to start of track */
			reply = stream_seek(l1_img->file_handle, track_offset, SEEK_SET);
			if (reply)
				return 1;
			/* write remnant of sector */
			reply = stream_write(l1_img->file_handle, (UINT8 *)src + (track_len-sector_offset), 256-(track_len-sector_offset));
			if (reply != 256-(track_len-sector_offset))
				return 1;
		}
		break;

	case if_harddisk:
		/* not implemented */
		assert(1);
		/*return imghd_write(l1_img->harddisk_handle, ((address->cylinder*l1_img->geometry.heads) + address->side)*l1_img->geometry.secspertrack + address->sector, 1, src) != 1;*/
		break;
	}

	return 0;
}

/*
	Convert physical record address to sector address (DSK format)

	aphysrec (I): absolute physrec address
	geometry (I): disk image geometry
	address (O): physical sector address
*/
static void dsk_aphysrec_to_sector_address(int aphysrec, const ti99_geometry *geometry, ti99_sector_address *address)
{
	address->sector = aphysrec % geometry->secspertrack;
	aphysrec /= geometry->secspertrack;
	address->cylinder = aphysrec % geometry->cylinders;
	address->side = aphysrec / geometry->cylinders;
	if (address->side & 1)
		/* on side 1, tracks are stored in the reverse order */
		address->cylinder = geometry->cylinders-1 - address->cylinder;
}

/*
	Convert physical record address to sector address (WIN format for HFDC)

	Note that physical address translation makes sense for HFDC, but not SCSI.

	aphysrec (I): absolute physrec address
	geometry (I): disk image geometry
	address (O): physical sector address
*/
/*static void win_aphysrec_to_sector_address(int aphysrec, const ti99_geometry *geometry, ti99_sector_address *address)
{
	address.sector = aphysrec % l1_img->geometry.secspertrack;
	aphysrec /= l1_img->geometry.secspertrack;
	address.side = aphysrec % l1_img->geometry.heads;
	address.cylinder = aphysrec / l1_img->geometry.heads;
}*/

/*
	Read one 256-byte physical record from a disk image

	l1_img (I/O): level-1 image handle
	aphysrec (I): absolute physrec address
	dest (O): pointer to 256-byte destination buffer

	Return non-zero on error
*/
static int read_absolute_physrec(ti99_lvl1_imgref *l1_img, unsigned aphysrec, void *dest)
{
	ti99_sector_address address;


	if (l1_img->img_format == if_harddisk)
	{
		/*win_aphysrec_to_sector_address(aphysrec, & l1_img->geometry, & address);

		return read_sector(l1_img, & address, dest);*/

		return imghd_read(&l1_img->harddisk_handle, aphysrec, 1, dest) != IMGTOOLERR_SUCCESS;
	}
	else
	{
		dsk_aphysrec_to_sector_address(aphysrec, & l1_img->geometry, & address);

		return read_sector(l1_img, & address, dest);
	}
}

/*
	Write one 256-byte physical record to a disk image

	l1_img (I/O): level-1 image handle
	aphysrec (I): absolute physrec address
	src (I): pointer to 256-byte source buffer

	Return non-zero on error
*/
static int write_absolute_physrec(ti99_lvl1_imgref *l1_img, unsigned aphysrec, const void *src)
{
	ti99_sector_address address;


	if (l1_img->img_format == if_harddisk)
	{
		/*win_aphysrec_to_sector_address(aphysrec, & l1_img->geometry, & address);

		return write_sector(l1_img, & address, dest);*/

		return imghd_write(&l1_img->harddisk_handle, aphysrec, 1, src) != IMGTOOLERR_SUCCESS;
	}
	else
	{
		dsk_aphysrec_to_sector_address(aphysrec, & l1_img->geometry, & address);

		return write_sector(l1_img, & address, src);
	}
}

#if 0
#pragma mark -
#pragma mark LEVEL 2 DISK ROUTINES
#endif

/*
	Level 2 implements files as a succession of 256-byte-long physical records.

	Level 2 implements allocation bitmap (and AU), disk catalog, etc.
*/

/*
	WIN VIB/DDR record
*/
typedef struct win_vib_ddr
{
	char name[10];			/* disk volume name (10 characters, pad with spaces) */
	UINT16BE totAUs;		/* total number of AUs */
	UINT8 secspertrack;		/* HFDC: sectors per track (typically 32) */
							/* SCSI: reserved */
	union
	{
		struct
		{
			UINT8 id[3];	/* V1 VIB: 'WIN' */
		} vib_v1;

		struct				/* V2 VIB: extra params */
		{
			UINT8 res_AUs;	/* # AUs reserved for vib, bitmap, ddr, fdir and fdr, divided by 64 */
			UINT8 step_spd;	/* HFDC: step speed (0-7) */
							/* SCSI: reserved */
			UINT8 red_w_cur;/* HFDC: reduced write current cylinder, divided by 8 */
							/* SCSI: reserved */
		} vib_v2;

		struct
		{
			UINT8 id[3];	/* DDR: 'DIR' */
		} ddr;
	} u;
	UINT16BE params;		/* bits 0-3: sectors/AU - 1 */
							/* HFDC: */
								/* bits 4-7: # heads - 1 */
								/* bit 8: V1: buffered head stepping flag */
								/*        V2: reserved */
								/* bit 9-15: write precompensation track, divided by 16 */
							/* SCSI: */
								/* bits 4-15: reserved */
	ti99_date_time creation;/* date and time of creation */
	UINT8 num_files;		/* number of files in directory */
	UINT8 num_subdirs;		/* number of subdirectories in directory */
	UINT16BE fdir_AU;		/* points to root directory fdir */
	union
	{
		struct
		{
			UINT16BE dsk1_AU;	/* HFDC: points to current dsk1 emulation image (0 if none) */
								/* SCSI: reserved */
		} vib;

		struct
		{
			UINT16BE parent_ddr_AU;	/* points to parent directory DDR */
		} ddr;
	} u2;
	UINT16BE subdir_AU[114];/* points to all subdirectory DDRs */
} win_vib_ddr;

/*
	AU format
*/
typedef struct ti99_AUformat
{
	int totAUs;				/* total number of AUs */
	int physrecsperAU;		/* number of 256-byte physical records per AU */
} ti99_AUformat;

/*
	DSK directory reference: 0 for root, 1 for 1st subdir, 2 for 2nd subdir, 3
	for 3rd subdir
*/
/*typedef int dir_ref;*/

/*
	catalog entry (used for in-memory catalog)
*/
typedef struct dir_entry
{
	UINT16 dir_ptr;			/* DSK: unused */
							/* WIN: AU address of the DDR for this directory */
	char name[10];			/* name of this directory (copied from the VIB for DSK, DDR for WIN) */
} dir_entry;

typedef struct file_entry
{
	UINT16 fdr_ptr;			/* DSK: aphysrec address of the FDR for this file */
							/* WIN: AU address of the FDR for this file */
	char name[10];			/* name of this file (copied from FDR) */
} file_entry;

typedef struct ti99_catalog
{
	int num_subdirs;		/* number of subdirectories */
	int num_files;			/* number of files */
	dir_entry subdirs[114];	/* description of each subdir */
	file_entry files[128];	/* description of each file */
} ti99_catalog;

/*
	level-2 disk image descriptor
*/
typedef struct ti99_lvl2_imgref_dsk
{
	UINT16 totphysrecs;				/* total number of aphysrecs (extracted from vib record in aphysrec 0) */
	ti99_catalog catalogs[4];		/* catalog of root directory and up to 3 subdirectories */
	UINT16 fdir_aphysrec[4];		/* fdir aphysrec address for root directory
										and up to 3 subdirectories */
} ti99_lvl2_imgref_dsk;

typedef struct ti99_lvl2_imgref_win
{
	enum
	{
		win_vib_v1,
		win_vib_v2
	} vib_version;			/* version of the vib record in aphysrec 0 (see win_vib_ddr) */
} ti99_lvl2_imgref_win;

typedef struct ti99_lvl2_imgref
{
	ti99_lvl1_imgref l1_img;/* image format, imgtool image handle, image geometry */
	ti99_AUformat AUformat;	/* AU format */
	int data_offset;		/* In order to reduce seek times when searching the
								disk for a given file name, fdr (and ddr, and
								fdir) records are preferentially allocated in
								AUs n to data_offset, whereas data records are
								preferentially allocated in AUs starting at
								data_offset. */
							/* With the DSK disk structure, n is always 2 (if 1
								physrec per AU) or 1 (if 2 physrecs per AU or
								more), and data_offset is arbitrarily chosen as
								34. */
							/* With the WIN disk structure, n depends on the
								size of the volume bitmap, which itself depends
								on the number of AUs on disk (we always have n
								<= 33), and data_offset is read from the vib
								record (except with the obsolete v1 VIB, where
								we use a default value of 64). */
	char vol_name[10];		/* cached volume name (extracted from vib record in aphysrec 0) */

	UINT8 abm[8192];		/* allocation bitmap */

	enum
	{
		L2I_DSK,
		L2I_WIN
	} type;					/* structure format */

	union
	{
		ti99_lvl2_imgref_dsk dsk;
		ti99_lvl2_imgref_win win;
	} u;					/* structure-specific info */
} ti99_lvl2_imgref;

/*
	file flags found in fdr (and tifiles)
*/
enum
{
	fdr99_f_program	= 0x01,	/* set for program files */
	fdr99_f_int		= 0x02,	/* set for binary files */
	fdr99_f_wp		= 0x08,	/* set if file is write-protected */
	/*fdr99_f_backup	= 0x10,*/	/* set if file has been modified since last backup */
	/*fdr99_f_dskimg	= 0x20,*/	/* set if file is a DSK image (HFDC HD only) */
	fdr99_f_var		= 0x80	/* set if file uses variable-length records*/
};

/*
	DSK FDR record
*/
typedef struct dsk_fdr
{
	char name[10];			/* file name (10 characters, pad with spaces) */
	UINT16BE xreclen;		/* extended record len: if record len is >= 256, */
								/* reclen is set to 0 and the actual reclen is */
								/* stored here (Myarc HFDC only).  TI reserved */
								/* this  field for data chain pointer extension, */
								/* but this was never implemented. */
	UINT8 flags;			/* file status flags (see enum above) */
	UINT8 recsperphysrec;	/* logical records per physrec */
								/* ignored for variable length record files and */
								/* program files */
	UINT16BE fphysrecs;		/* file length in physrecs */
								/* Note that the HFDC defines this field as the */
								/* number of allocated physrecs in the cluster */
								/* chain (i.e. rounded on the next AU */
								/* boundary), so level-3 routines should use */
								/* the fixrecs field instead to determine the */
								/* logical lenght of field.  IIRC, the HFDC */
								/* implementation is regarded as a bug because */
								/* program files do not define the fixrecs field */
								/* field, so program field saved by the HFDC */
								/* DSR may be larger whan they should. */
	UINT8 eof;				/* EOF offset in last physrec for variable length */
								/* record files and program files (0->256)*/
	UINT8 reclen;			/* logical record size in bytes ([1,255] 0->256) */
								/* Maximum allowable record size for variable */
								/* length record files.  Reserved for program */
								/* files (set to 0).  Set to 0 if reclen >=256 */
								/* (HFDC only). */
	UINT16LE fixrecs;		/* file length in logical records */
								/* For variable length record files, number of */
								/* 256-byte records actually used. */
	ti99_date_time creation;/* date and time of creation (HFDC and BwG only; */
								/* reserved in TI) */
	ti99_date_time update;	/* date and time of last write to file (HFDC and */
								/* BwG only; reserved in TI) */
	UINT8 clusters[76][3];	/* data cluster table: 0 through 76 entries (3 */
								/* bytes each), one entry for each file cluster. */
								/* 12 bits: address of first AU of cluster */
								/* 12 bits: offset of last 256-byte record in cluster */
} dsk_fdr;

/*
	WIN FDR record
*/
typedef struct win_fdr
{
	char name[10];			/* file name (10 characters, pad with spaces) */
	UINT16BE xreclen;		/* extended record len: if record len is >= 256, */
								/* reclen is set to 0 and the actual reclen is */
								/* stored here (Myarc HFDC only).  TI reserved */
								/* this  field for data chain pointer extension, */
								/* but this was never implemented. */
	UINT8 flags;			/* file status flags (see enum above) */
	UINT8 recsperphysrec;	/* logical records per physrec */
								/* ignored for variable length record files and */
								/* program files */
	UINT16BE fphysrecs_LSW;	/* eldest FDR: file length in physrecs */
								/* Note that the HFDC defines this field as the */
								/* number of allocated physrecs in the cluster */
								/* chain (i.e. rounded on the next AU */
								/* boundary), so level-3 routines should use */
								/* the fixrecs field instead to determine the */
								/* logical lenght of field.  IIRC, the HFDC */
								/* implementation is regarded as a bug because */
								/* program files do not define the fixrecs field */
								/* field, so program field saved by the HFDC */
								/* DSR may be larger whan they should. */
							/* other sibling FDRs: index of the first file */
								/* physrec in this particular sibling FDR */
	UINT8 eof;				/* EOF offset in last physrec for variable length */
								/* record files and program files (0->256)*/
	UINT8 reclen;			/* logical record size in bytes ([1,255]) */
								/* Maximum allowable record size for variable */
								/* length record files.  Reserved for program */
								/* files (set to 0).  Set to 0 if reclen >=256 */
								/* (HFDC only). */
	UINT16LE fixrecs_LSW;	/* file length in logical records */
								/* For variable length record files, number of */
								/* 256-byte records actually used. */
	ti99_date_time creation;/* date and time of creation */
	ti99_date_time update;	/* date and time of last write to file */

	char id[2];				/* 'FI' */
	UINT16BE prevsibFDR_AU;	/* address of the AU where previous sibling FDR is */
								/* (see also xinfo_LSB) */
	UINT16BE nextsibFDR_AU;	/* address of the AU where next sibling FDR is */
								/* (see also xinfo_LSB) */
	UINT16BE sibFDR_AUlen;	/* total number of data AUs allocated in this particular sibling FDR */
	UINT16BE parent_FDIR_AU;/* FDIR the file is listed in */
	UINT8 xinfo_MSB;		/* extended information (MSByte) */
								/* bits 0-3: MSN of fphysrecs */
								/* bits 4-7: MSN of fixrecs */
	UINT8 xinfo_LSB;		/* extended information (LSByte) */
								/* bits 8-11: physrec offset within AU for */
									/* previous sibling FDR (see prevsibFDR_AU) */
								/* bits 12-15: physrec offset within AU for */
									/* next sibling FDR (see nextsibFDR_AU) */
	UINT16BE clusters[54][2];/* data cluster table: 0 through 54 entries (4 */
								/* bytes each), one entry for each file cluster. */
								/* 16 bits: address of first AU of cluster */
								/* 16 bits: address of last AU of cluster */
} win_fdr;

/*
	tifile header: stand-alone file 
*/
typedef struct tifile_header
{
	char tifiles[8];		/* always '\7TIFILES' */
	UINT16BE fphysrecs;		/* file length in physrecs */
	UINT8 flags;			/* see enum above */
	UINT8 recsperphysrec;	/* records per physrec */
	UINT8 eof;				/* current position of eof in last physrec (0->255)*/
	UINT8 reclen;			/* bytes per record ([1,255] 0->256) */
	UINT16BE fixrecs;		/* file length in records */
	UINT8 res[128-16];		/* reserved */
								/* * variant a: */
									/* 112 chars: 0xCA53 repeated 56 times */
								/* * variant b: */
									/* 4 chars: unknown */
									/* 108 chars: 0xCA53 repeated 54 times */
								/* * variant c: */
									/* 10 chars: original TI file name filed with spaces */
									/* 102 chars: spaces */
								/* * variant d: */
									/* 10 chars: original TI file name filed with spaces */
									/* 2 chars: CR+LF */
									/* 98 chars: spaces */
									/* 2 chars: CR+LF */
								/* * variant e: */
									/* 10 chars: original TI file name */
									/* 4 bytes: unknown */
									/* 4 bytes: time & date of creation */
									/* 4 bytes: time & date of last update */
									/* 90 chars: spaces */
								/* * variant f: */
									/* 6 bytes: 'MYTERM' */
									/* 4 bytes: time & date of creation */
									/* 4 bytes: time & date of last update */
									/* 2 bytes: unknown (always >0000) */
									/* 96 chars: 0xCA53 repeated 56 times */
} tifile_header;

/*
	level-2 file descriptor
*/
typedef struct ti99_lvl2_fileref_dsk
{
	ti99_lvl2_imgref *l2_img;
	int fdr_aphysrec;
	dsk_fdr fdr;
} ti99_lvl2_fileref_dsk;

typedef struct ti99_lvl2_fileref_win
{
	ti99_lvl2_imgref *l2_img;
	unsigned fphysrecs;				/* copy of field in the eldest FDR */
	unsigned eldestfdr_aphysrec;	/* aphysrec address of the eldest FDR */
	unsigned curfdr_aphysrec;		/* aphysrec address of the currently open sibling FDR */
	win_fdr curfdr;					/* buffer with currently open sibling FDR */
} ti99_lvl2_fileref_win;

typedef struct ti99_lvl2_fileref_tifiles
{
	imgtool_stream *file_handle;
	tifile_header hdr;
} ti99_lvl2_fileref_tifiles;

typedef struct ti99_lvl2_fileref
{
	enum
	{
		L2F_DSK,
		L2F_WIN,
		L2F_TIFILES
	} type;
	union
	{
		ti99_lvl2_fileref_dsk dsk;
		ti99_lvl2_fileref_win win;
		ti99_lvl2_fileref_tifiles tifiles;
	} u;
} ti99_lvl2_fileref;



/*
	Compare two (possibly empty) catalog entry for qsort
*/
static int cat_file_compare_qsort(const void *p1, const void *p2)
{
	const file_entry *entry1 = p1;
	const file_entry *entry2 = p2;

	if ((entry1->fdr_ptr == 0) && (entry2->fdr_ptr == 0))
		return 0;
	else if (entry1->fdr_ptr == 0)
		return +1;
	else if (entry2->fdr_ptr == 0)
		return -1;
	else
		return memcmp(entry1->name, entry2->name, 10);
}

static int cat_dir_compare_qsort(const void *p1, const void *p2)
{
	const dir_entry *entry1 = p1;
	const dir_entry *entry2 = p2;

	if ((entry1->dir_ptr == 0) && (entry2->dir_ptr == 0))
		return 0;
	else if (entry1->dir_ptr == 0)
		return +1;
	else if (entry2->dir_ptr == 0)
		return -1;
	else
		return memcmp(entry1->name, entry2->name, 10);
}

/*
	Read a directory catalog from disk image

	l2_img: image reference
	aphysrec: physical record address of the FDIR
	dest: pointer to the destination buffer where the catalog should be written

	Return an error code if there was an error, 0 otherwise.
*/
static int dsk_read_catalog(ti99_lvl2_imgref *l2_img, int aphysrec, ti99_catalog *dest)
{
	int totphysrecs = l2_img->u.dsk.totphysrecs;
	UINT16BE fdir_buf[128];
	dsk_fdr fdr;
	int i;
	int reply;


	/* Read FDIR record */
	reply = read_absolute_physrec(& l2_img->l1_img, aphysrec, fdir_buf);
	if (reply)
		return IMGTOOLERR_READERROR;

	/* Copy FDIR info to catalog structure */
	for (i=0; i<128; i++)
		dest->files[i].fdr_ptr = get_UINT16BE(fdir_buf[i]);

	/* Check FDIR pointers and check and extract file names from DDRs */
	for (i=0; i<128; i++)
	{
		if (dest->files[i].fdr_ptr >= totphysrecs)
		{
			return IMGTOOLERR_CORRUPTIMAGE;
		}
		else if (dest->files[i].fdr_ptr)
		{
			reply = read_absolute_physrec(& l2_img->l1_img, dest->files[i].fdr_ptr, &fdr);
			if (reply)
				return IMGTOOLERR_READERROR;

			/* check and copy file name */
			if (check_fname(fdr.name))
				return IMGTOOLERR_CORRUPTIMAGE;
			memcpy(dest->files[i].name, fdr.name, 10);
		}
	}

	/* Check catalog */
	for (i=0; i<127; i++)
	{
		if (((! dest->files[i].fdr_ptr) && dest->files[i+1].fdr_ptr)
			|| ((dest->files[i].fdr_ptr && dest->files[i+1].fdr_ptr) && (memcmp(dest->files[i].name, dest->files[i+1].name, 10) >= 0)))
		{
			/* if the catalog is not sorted, we repair it */
			qsort(dest->files, sizeof(dest->files)/sizeof(dest->files[0]), sizeof(dest->files[0]),
					cat_file_compare_qsort);
			break;
		}
	}

	/* Set file count */
	for (i=0; (i<128) && (dest->files[i].fdr_ptr != 0); i++)
		;
	dest->num_files = i;

	/* Set subdir count to 0 (subdirs are loaded elsewhere) */
	dest->num_subdirs = 0;

	return 0;
}

/*
	Read a directory catalog from disk image

	l2_img: image reference
	DDR_AU: AU address of the VIB/DDR
	dest: pointer to the destination buffer where the catalog should be written

	Return an error code if there was an error, 0 otherwise.
*/
static int win_read_catalog(ti99_lvl2_imgref *l2_img, int DDR_AU, ti99_catalog *dest)
{
	win_vib_ddr ddr_buf;
	UINT16BE fdir_buf[128];
	win_fdr fdr_buf;
	int i;
	int reply;


	/* Read DDR record */
	reply = read_absolute_physrec(& l2_img->l1_img, DDR_AU*l2_img->AUformat.physrecsperAU, &ddr_buf);
	if (reply)
		return IMGTOOLERR_READERROR;

	/* sanity checks */
	if ((ddr_buf.num_files > 127) || (ddr_buf.num_subdirs > 114) || (get_UINT16BE(ddr_buf.fdir_AU) > l2_img->AUformat.totAUs))
		return IMGTOOLERR_CORRUPTIMAGE;

	/* set file count and subdir count */
	dest->num_files = ddr_buf.num_files;
	dest->num_subdirs = ddr_buf.num_subdirs;

	/* Copy DDR info to catalog structure */
	for (i=0; i<ddr_buf.num_subdirs; i++)
		dest->subdirs[i].dir_ptr = get_UINT16BE(ddr_buf.subdir_AU[i]);

	/* Read FDIR record */
	reply = read_absolute_physrec(& l2_img->l1_img, get_UINT16BE(ddr_buf.fdir_AU)*l2_img->AUformat.physrecsperAU, fdir_buf);
	if (reply)
		return IMGTOOLERR_READERROR;

	/* Copy FDIR info to catalog structure */
	for (i=0; i<dest->num_files; i++)
		dest->files[i].fdr_ptr = get_UINT16BE(fdir_buf[i]);

	/* Check DDR pointers and check and extract file names from FDRs */
	for (i=0; i<dest->num_subdirs; i++)
	{
		if (dest->subdirs[i].dir_ptr >= l2_img->AUformat.totAUs)
		{
			return IMGTOOLERR_CORRUPTIMAGE;
		}
		else if (dest->subdirs[i].dir_ptr)
		{
			reply = read_absolute_physrec(& l2_img->l1_img, dest->subdirs[i].dir_ptr*l2_img->AUformat.physrecsperAU, &ddr_buf);
			if (reply)
				return IMGTOOLERR_READERROR;

			/* check and copy file name */
			if (check_fname(ddr_buf.name))
				return IMGTOOLERR_CORRUPTIMAGE;
			memcpy(dest->subdirs[i].name, ddr_buf.name, 10);
		}
	}

	/* Check FDIR pointers and check and extract file names from FDRs */
	for (i=0; i<dest->num_files; i++)
	{
		if (dest->files[i].fdr_ptr >= l2_img->AUformat.totAUs)
		{
			return IMGTOOLERR_CORRUPTIMAGE;
		}
		else if (dest->files[i].fdr_ptr)
		{
			reply = read_absolute_physrec(& l2_img->l1_img, dest->files[i].fdr_ptr*l2_img->AUformat.physrecsperAU, &fdr_buf);
			if (reply)
				return IMGTOOLERR_READERROR;

			/* check and copy file name */
			if (check_fname(fdr_buf.name))
				return IMGTOOLERR_CORRUPTIMAGE;
			memcpy(dest->files[i].name, fdr_buf.name, 10);
		}
	}

	/* Check catalog */

	/* Check subdir order */
	for (i=0; i<dest->num_subdirs-1; i++)
	{
		if (((! dest->subdirs[i].dir_ptr) && dest->subdirs[i+1].dir_ptr)
			|| ((dest->subdirs[i].dir_ptr && dest->subdirs[i+1].dir_ptr) && (memcmp(dest->subdirs[i].name, dest->subdirs[i+1].name, 10) >= 0)))
		{
			/* if the subdir catalog is not sorted, we repair it */
			qsort(dest->subdirs, dest->num_subdirs, sizeof(dest->subdirs[0]), cat_dir_compare_qsort);
			break;
		}
	}

	/* Fix subdir count */
	while (dest->num_subdirs && (dest->subdirs[dest->num_subdirs-1].dir_ptr == 0))
		dest->num_subdirs--;

	/* Check file order */
	for (i=0; i<dest->num_files-1; i++)
	{
		if (((! dest->files[i].fdr_ptr) && dest->files[i+1].fdr_ptr)
			|| ((dest->files[i].fdr_ptr && dest->files[i+1].fdr_ptr) && (memcmp(dest->files[i].name, dest->files[i+1].name, 10) >= 0)))
		{
			/* if the file catalog is not sorted, we repair it */
			qsort(dest->files, dest->num_files, sizeof(dest->files[0]), cat_file_compare_qsort);
			break;
		}
	}

	/* Fix file count */
	while (dest->num_files && (dest->files[dest->num_files-1].fdr_ptr == 0))
		dest->num_files--;

	return 0;
}

/*
	Search for a file path on a floppy image

	l2_img: image reference
	fpath: path of the file to search
	parent_ref_valid: set to TRUE if either the file was found or the file was
		not found but its parent dir was
	parent_ref: reference to parent dir (0 for root)
	out_is_dir: TRUE if element is a directory
	catalog_index: on output, index of file catalog entry (may be NULL)
*/
static int dsk_find_catalog_entry(ti99_lvl2_imgref *l2_img, const char *fpath, int *parent_ref_valid, int *parent_ref, int *out_is_dir, int *catalog_index)
{
	int i;
	const ti99_catalog *cur_catalog;
	const char *element_start, *element_end;
	int element_len;
	char element[10];
	int is_dir = FALSE;


	cur_catalog = & l2_img->u.dsk.catalogs[0];
	if (parent_ref_valid)
		(* parent_ref_valid) = FALSE;
	if (parent_ref)
		*parent_ref = 0;

	element_start = fpath;
	do
	{
		/* find next path element */
		element_end = strchr(element_start, '.');
		element_len = element_end ? (element_end - element_start) : strlen(element_start);
		if ((element_len > 10) || (element_len == 0))
			return IMGTOOLERR_BADFILENAME;
		/* last path element */
		if ((!element_end) && parent_ref_valid)
			(* parent_ref_valid) = TRUE;

		/* generate file name */
		memcpy(element, element_start, element_len);
		memset(element+element_len, ' ', 10-element_len);

		/* search entry in subdirectories */
		for (i = 0; i<cur_catalog->num_subdirs; i++)
		{
			if (! memcmp(element, cur_catalog->subdirs[i].name, 10))
			{
				is_dir = TRUE;
				break;
			}
		}

		/* if it failed, search entry in files */
		if (i == cur_catalog->num_subdirs)
		{
			for (i = 0; i<cur_catalog->num_files; i++)
			{
				if (! memcmp(element, cur_catalog->files[i].name, 10))
				{
					is_dir = FALSE;
					break;
				}
			}
			/* exit if not found */
			if (i == cur_catalog->num_files)
			{
				return IMGTOOLERR_FILENOTFOUND;
			}
		}

		/* iterate */
		if (element_end)
		{
			element_start = element_end+1;

			if (! is_dir)
				/* this is not a directory */
				return IMGTOOLERR_BADFILENAME;

			/* initialize cur_catalog */
			cur_catalog = & l2_img->u.dsk.catalogs[i+1];
			if (parent_ref)
				*parent_ref = i+1;
		}
		else
			element_start = NULL;
	}
	while (element_start);

	if (out_is_dir)
		*out_is_dir = is_dir;

	if (catalog_index)
		*catalog_index = i;

	return 0;
}

/*
	Search for a file path on a harddisk image

	l2_img: image reference
	fpath: path of the file to search
	parent_ref_valid: set to TRUE if either the file was found or the file was
		not found but its parent dir was
	parent_ddr_AU: parent DDR AU address (0 for root)
	parent_catalog: catalog of parent dir (cannot be NULL)
	out_is_dir: TRUE if element is a directory
	catalog_index: on output, index of file catalog entry (may be NULL)
*/
static int win_find_catalog_entry(ti99_lvl2_imgref *l2_img, const char *fpath,
									int *parent_ref_valid, int *parent_ddr_AU, ti99_catalog *parent_catalog,
									int *out_is_dir, int *catalog_index)
{
	int i;
	const char *element_start, *element_end;
	int element_len;
	char element[10];
	int is_dir = FALSE;
	int errorcode;

	if (parent_ref_valid)
		(* parent_ref_valid) = FALSE;
	if (parent_ddr_AU)
		*parent_ddr_AU = 0;

	errorcode = win_read_catalog(l2_img, 0, parent_catalog);
	if (errorcode)
		return errorcode;

	element_start = fpath;
	do
	{
		/* find next path element */
		element_end = strchr(element_start, '.');
		element_len = element_end ? (element_end - element_start) : strlen(element_start);
		if ((element_len > 10) || (element_len == 0))
			return IMGTOOLERR_BADFILENAME;
		/* last path element */
		if ((!element_end) && parent_ref_valid)
			(* parent_ref_valid) = TRUE;

		/* generate file name */
		memcpy(element, element_start, element_len);
		memset(element+element_len, ' ', 10-element_len);

		/* search entry in subdirectories */
		for (i = 0; i<parent_catalog->num_subdirs; i++)
		{
			if (! memcmp(element, parent_catalog->subdirs[i].name, 10))
			{
				is_dir = TRUE;
				break;
			}
		}

		/* if it failed, search entry in files */
		if (i == parent_catalog->num_subdirs)
		{
			for (i = 0; i<parent_catalog->num_files; i++)
			{
				if (! memcmp(element, parent_catalog->files[i].name, 10))
				{
					is_dir = FALSE;
					break;
				}
			}
			/* exit if not found */
			if (i == parent_catalog->num_files)
			{
				return IMGTOOLERR_FILENOTFOUND;
			}
		}

		/* iterate */
		if (element_end)
		{
			element_start = element_end+1;

			if (! is_dir)
				/* this is not a directory */
				return IMGTOOLERR_BADFILENAME;

			if (parent_ddr_AU)
				*parent_ddr_AU = parent_catalog->subdirs[i].dir_ptr;

			errorcode = win_read_catalog(l2_img, parent_catalog->subdirs[i].dir_ptr, parent_catalog);
			if (errorcode)
				return errorcode;
		}
		else
			element_start = NULL;
	}
	while (element_start);

	if (out_is_dir)
		*out_is_dir = is_dir;

	if (catalog_index)
		*catalog_index = i;

	return 0;
}

/*
	Allocate one AU on disk, for use as a fdr record

	l2_img: image reference
	fdr_AU: on output, address of allocated AU
*/
static int alloc_fdr_AU(ti99_lvl2_imgref *l2_img, unsigned *fdr_AU)
{
	int totAUs = l2_img->AUformat.totAUs;
	int i;

	for (i=0; i<totAUs; i++)
	{
		if (! (l2_img->abm[i >> 3] & (1 << (i & 7))))
		{
			*fdr_AU = i;
			l2_img->abm[i >> 3] |= 1 << (i & 7);

			return 0;
		}
	}

	return IMGTOOLERR_NOSPACE;
}

INLINE int get_dsk_fdr_cluster_baseAU(ti99_lvl2_imgref *l2_img, dsk_fdr *fdr, int cluster_index)
{
	int reply;

	/* read base AU/physrec for this cluster */
	reply = ((fdr->clusters[cluster_index][1] & 0xf) << 8) | fdr->clusters[cluster_index][0];
	/* convert to AU address */
	if (l2_img->AUformat.physrecsperAU <= 2)
		reply /= l2_img->AUformat.physrecsperAU;

	return reply;
}

INLINE int get_dsk_fdr_cluster_baseaphysrec(ti99_lvl2_imgref *l2_img, dsk_fdr *fdr, int cluster_index)
{
	int reply;

	/* read base AU/physrec for this cluster */
	reply = ((fdr->clusters[cluster_index][1] & 0xf) << 8) | fdr->clusters[cluster_index][0];
	/* convert to physrec address */
	if (l2_img->AUformat.physrecsperAU > 2)
		reply *= l2_img->AUformat.physrecsperAU;

	return reply;
}

INLINE int get_dsk_fdr_cluster_lastfphysrec(dsk_fdr *fdr, int cluster_index)
{
	return (fdr->clusters[cluster_index][2] << 4) | (fdr->clusters[cluster_index][1] >> 4);
}

INLINE void set_dsk_fdr_cluster_lastfphysrec(dsk_fdr *fdr, int cluster_index, int data)
{
	fdr->clusters[cluster_index][1] = (fdr->clusters[cluster_index][1] & 0x0f) | (data << 4);
	fdr->clusters[cluster_index][2] = data >> 4;
}

INLINE void set_dsk_fdr_cluster(ti99_lvl2_imgref *l2_img, dsk_fdr *fdr, int cluster_index, int baseAU, int lastfphysrec)
{
	/* convert AU address to FDR value */
	if (l2_img->AUformat.physrecsperAU <= 2)
		baseAU *= l2_img->AUformat.physrecsperAU;

	/* write cluster entry */
	fdr->clusters[cluster_index][0] = baseAU;
	fdr->clusters[cluster_index][1] = ((baseAU >> 8) & 0x0f) | (lastfphysrec << 4);
	fdr->clusters[cluster_index][2] = lastfphysrec >> 4;
}

INLINE unsigned get_win_fdr_fphysrecs(win_fdr *fdr)
{
	return (((unsigned) fdr->xinfo_MSB << 12) & 0xf0000) | get_UINT16BE(fdr->fphysrecs_LSW);
}

INLINE void set_win_fdr_fphysrecs(win_fdr *fdr, unsigned data)
{
	fdr->xinfo_MSB = (fdr->xinfo_MSB & 0x0f) | ((data >> 12) & 0xf0);
	set_UINT16BE(&fdr->fphysrecs_LSW, data & 0xffff);
}

INLINE unsigned get_win_fdr_fixrecs(win_fdr *fdr)
{
	return (((unsigned) fdr->xinfo_MSB << 16) & 0xf0000) | get_UINT16LE(fdr->fixrecs_LSW);
}

INLINE void set_win_fdr_fixrecs(win_fdr *fdr, unsigned data)
{
	fdr->xinfo_MSB = (fdr->xinfo_MSB & 0xf0) | ((data >> 16) & 0x0f);
	set_UINT16LE(&fdr->fixrecs_LSW, data & 0xffff);
}

INLINE unsigned get_win_fdr_prevsibFDR_aphysrec(ti99_lvl2_imgref *l2_img, win_fdr *fdr)
{
	unsigned prevsibFDR_AU = get_UINT16BE(fdr->prevsibFDR_AU);

	return prevsibFDR_AU
			? (prevsibFDR_AU * l2_img->AUformat.physrecsperAU + ((fdr->xinfo_LSB >> 4) & 0xf))
			: 0;
}

INLINE unsigned get_win_fdr_nextsibFDR_aphysrec(ti99_lvl2_imgref *l2_img, win_fdr *fdr)
{
	unsigned nextsibFDR_AU = get_UINT16BE(fdr->nextsibFDR_AU);

	return nextsibFDR_AU
			? (nextsibFDR_AU * l2_img->AUformat.physrecsperAU + (fdr->xinfo_LSB & 0xf))
			: 0;
}

INLINE unsigned get_win_fdr_cursibFDR_basefphysrec(win_fdr *fdr)
{
	return get_UINT16BE(fdr->prevsibFDR_AU) ? get_win_fdr_fphysrecs(fdr) : 0;
}

/*
	Advance to next sibling FDR
*/
static int win_goto_next_sibFDR(ti99_lvl2_fileref_win *win_file)
{
	if (get_UINT16BE(win_file->curfdr.nextsibFDR_AU) == 0)
		return IMGTOOLERR_UNEXPECTED;

	win_file->curfdr_aphysrec = get_win_fdr_nextsibFDR_aphysrec(win_file->l2_img, &win_file->curfdr);
	if (read_absolute_physrec(& win_file->l2_img->l1_img, win_file->curfdr_aphysrec, &win_file->curfdr))
		return IMGTOOLERR_READERROR;

	return 0;
}

/*
	Back to previous sibling FDR
*/
static int win_goto_prev_sibFDR(ti99_lvl2_fileref_win *win_file)
{
	if (get_UINT16BE(win_file->curfdr.prevsibFDR_AU) == 0)
		return IMGTOOLERR_UNEXPECTED;

	win_file->curfdr_aphysrec = get_win_fdr_prevsibFDR_aphysrec(win_file->l2_img, &win_file->curfdr);
	if (read_absolute_physrec(& win_file->l2_img->l1_img, win_file->curfdr_aphysrec, &win_file->curfdr))
		return IMGTOOLERR_READERROR;

	return 0;
}

/*
	Append a new sibling FDR at the end of the sibling FDR list, and open it.

	You must have gone to the end of the list.
*/
static int win_alloc_sibFDR(ti99_lvl2_fileref_win *win_file)
{
	unsigned oldfdr_AU, oldfdr_physrecinAU;
	unsigned newfdr_AU, newfdr_physrecinAU;
	int allocated = FALSE;
	int errorcode;
	unsigned cursibFDR_basefphysrec;

	if (get_UINT16BE(win_file->curfdr.nextsibFDR_AU))
		return IMGTOOLERR_UNEXPECTED;

	oldfdr_AU = win_file->curfdr_aphysrec / win_file->l2_img->AUformat.physrecsperAU;
	oldfdr_physrecinAU = win_file->curfdr_aphysrec % win_file->l2_img->AUformat.physrecsperAU;

	if (oldfdr_physrecinAU != (win_file->l2_img->AUformat.physrecsperAU - 1))
	{	/* current AU is not full */
		newfdr_AU = oldfdr_AU;
		newfdr_physrecinAU = oldfdr_physrecinAU + 1;
	}
	else
	{	/* current AU is full: allocate another */
		errorcode = alloc_fdr_AU(win_file->l2_img, &newfdr_AU);
		if (errorcode)
			return errorcode;
		newfdr_physrecinAU = 0;
		allocated = TRUE;
	}

	set_UINT16BE(&win_file->curfdr.nextsibFDR_AU, newfdr_AU);
	win_file->curfdr.xinfo_LSB = (win_file->curfdr.xinfo_LSB & 0xf0) | newfdr_physrecinAU;

	/* save current sibling FDR */
	if (write_absolute_physrec(& win_file->l2_img->l1_img, win_file->curfdr_aphysrec, &win_file->curfdr))
	{
		/* clear pointer */
		set_UINT16BE(&win_file->curfdr.nextsibFDR_AU, 0);
		win_file->curfdr.xinfo_LSB = win_file->curfdr.xinfo_LSB & 0xf0;
		if (allocated)
			/* free AU */
			win_file->l2_img->abm[newfdr_AU >> 3] |= 1 << (newfdr_AU & 7);
		return IMGTOOLERR_WRITEERROR;
	}

	/* now update in-memory structure to describe new sibling FDR */
	cursibFDR_basefphysrec = get_win_fdr_cursibFDR_basefphysrec(&win_file->curfdr)
								+ get_UINT16BE(win_file->curfdr.sibFDR_AUlen) * win_file->l2_img->AUformat.physrecsperAU;

	set_UINT16BE(&win_file->curfdr.nextsibFDR_AU, 0);
	set_UINT16BE(&win_file->curfdr.prevsibFDR_AU, oldfdr_AU);
	win_file->curfdr.xinfo_LSB = oldfdr_physrecinAU << 4;

	win_file->curfdr_aphysrec = newfdr_AU * win_file->l2_img->AUformat.physrecsperAU + newfdr_physrecinAU;

	set_win_fdr_fphysrecs(&win_file->curfdr, cursibFDR_basefphysrec);
	set_UINT16BE(&win_file->curfdr.sibFDR_AUlen, 0);
	memset(win_file->curfdr.clusters, 0, sizeof(win_file->curfdr.clusters));

	return 0;
}

/*
	Extend a file with nb_alloc_physrecs extra physrecs

	dsk_file: file reference
	nb_alloc_physrecs: number of physical records to allocate
*/
static int dsk_alloc_file_physrecs(ti99_lvl2_fileref_dsk *dsk_file, int nb_alloc_physrecs)
{
	int totAUs = dsk_file->l2_img->AUformat.totAUs;
	int free_physrecs;
	int fphysrecs;
	int i;
	int cluster_index;
	int last_sec, p_last_sec = 0;
	int cur_block_seclen;
	int cluster_baseAU, cluster_AUlen;
	int first_best_block_baseAU = 0, first_best_block_seclen;
	int second_best_block_baseAU = 0, second_best_block_seclen;
	int search_start;

	/* compute free space */
	free_physrecs = 0;
	for (i=0; i<totAUs; i++)
	{
		if (! (dsk_file->l2_img->abm[i >> 3] & (1 << (i & 7))))
			free_physrecs += dsk_file->l2_img->AUformat.physrecsperAU;
	}

	/* check we have enough free space */
	if (free_physrecs < nb_alloc_physrecs)
		return IMGTOOLERR_NOSPACE;

	/* current number of data physrecs in file */
	fphysrecs = get_UINT16BE(dsk_file->fdr.fphysrecs);

	if (fphysrecs == 0)
	{	/* cluster array must be empty */
		cluster_index = 0;
	}
	else
	{	/* try to extend last block */
		last_sec = -1;
		for (cluster_index=0; cluster_index<76; cluster_index++)
		{
			p_last_sec = last_sec;
			last_sec = get_dsk_fdr_cluster_lastfphysrec(&dsk_file->fdr, cluster_index);
			if (last_sec >= (fphysrecs-1))
				break;
		}
		if (cluster_index == 76)
			/* that sucks */
			return IMGTOOLERR_CORRUPTIMAGE;

		if (last_sec > (fphysrecs-1))
		{	/* some extra space has already been allocated */
			cur_block_seclen = last_sec - (fphysrecs-1);
			if (cur_block_seclen > nb_alloc_physrecs)
				cur_block_seclen = nb_alloc_physrecs;

			fphysrecs += cur_block_seclen;
			set_UINT16BE(& dsk_file->fdr.fphysrecs, fphysrecs);
			nb_alloc_physrecs -= cur_block_seclen;
			if (! nb_alloc_physrecs)
				return 0;	/* done */
		}

		/* round up to next AU boundary */
		last_sec = last_sec + dsk_file->l2_img->AUformat.physrecsperAU - (last_sec % dsk_file->l2_img->AUformat.physrecsperAU) - 1;

		if (last_sec > (fphysrecs-1))
		{	/* some extra space has already been allocated */
			cur_block_seclen = last_sec - (fphysrecs-1);
			if (cur_block_seclen > nb_alloc_physrecs)
				cur_block_seclen = nb_alloc_physrecs;

			fphysrecs += cur_block_seclen;
			set_UINT16BE(& dsk_file->fdr.fphysrecs, fphysrecs);
			set_dsk_fdr_cluster_lastfphysrec(&dsk_file->fdr, cluster_index, fphysrecs-1);
			nb_alloc_physrecs -= cur_block_seclen;
			if (! nb_alloc_physrecs)
				return 0;	/* done */
		}

		/* read base AU address for this cluster */
		cluster_baseAU = get_dsk_fdr_cluster_baseAU(dsk_file->l2_img, &dsk_file->fdr, cluster_index);
		/* point past cluster end */
		cluster_baseAU += (last_sec-p_last_sec/*+file->l2_img->AUformat.physrecsperAU-1*/) / dsk_file->l2_img->AUformat.physrecsperAU;
		/* count free physrecs after last block */
		cur_block_seclen = 0;
		for (i=cluster_baseAU; (! (dsk_file->l2_img->abm[i >> 3] & (1 << (i & 7)))) && (cur_block_seclen < nb_alloc_physrecs) && (i < totAUs); i++)
			cur_block_seclen += dsk_file->l2_img->AUformat.physrecsperAU;
		if (cur_block_seclen)
		{	/* extend last block */
			if (cur_block_seclen > nb_alloc_physrecs)
				cur_block_seclen = nb_alloc_physrecs;

			fphysrecs += cur_block_seclen;
			set_UINT16BE(& dsk_file->fdr.fphysrecs, fphysrecs);
			last_sec += cur_block_seclen;
			nb_alloc_physrecs -= cur_block_seclen;
			set_dsk_fdr_cluster_lastfphysrec(&dsk_file->fdr, cluster_index, last_sec);
			cluster_AUlen = (cur_block_seclen + dsk_file->l2_img->AUformat.physrecsperAU - 1) / dsk_file->l2_img->AUformat.physrecsperAU;
			for (i=0; i<cluster_AUlen; i++)
				dsk_file->l2_img->abm[(i+cluster_baseAU) >> 3] |= 1 << ((i+cluster_baseAU) & 7);
			if (! nb_alloc_physrecs)
				return 0;	/* done */
		}
		cluster_index++;
		if (cluster_index == 76)
			/* that sucks */
			return IMGTOOLERR_NOSPACE;
	}

	search_start = dsk_file->l2_img->data_offset;	/* initially, search for free space only in data space */
	while (nb_alloc_physrecs)
	{
		/* find smallest data block at least nb_alloc_physrecs in lenght, and largest data block less than nb_alloc_physrecs in lenght */
		first_best_block_seclen = INT_MAX;
		second_best_block_seclen = 0;
		for (i=search_start; i<totAUs; i++)
		{
			if (! (dsk_file->l2_img->abm[i >> 3] & (1 << (i & 7))))
			{	/* found one free block */
				/* compute its lenght */
				cluster_baseAU = i;
				cur_block_seclen = 0;
				while ((i<totAUs) && (! (dsk_file->l2_img->abm[i >> 3] & (1 << (i & 7)))))
				{
					cur_block_seclen += dsk_file->l2_img->AUformat.physrecsperAU;
					i++;
				}
				/* compare to previous best and second-best blocks */
				if ((cur_block_seclen < first_best_block_seclen) && (cur_block_seclen >= nb_alloc_physrecs))
				{
					first_best_block_baseAU = cluster_baseAU;
					first_best_block_seclen = cur_block_seclen;
					if (cur_block_seclen == nb_alloc_physrecs)
						/* no need to search further */
						break;
				}
				else if ((cur_block_seclen > second_best_block_seclen) && (cur_block_seclen < nb_alloc_physrecs))
				{
					second_best_block_baseAU = cluster_baseAU;
					second_best_block_seclen = cur_block_seclen;
				}
			}
		}

		if (first_best_block_seclen != INT_MAX)
		{	/* found one contiguous block which can hold it all */
			fphysrecs += nb_alloc_physrecs;
			set_UINT16BE(& dsk_file->fdr.fphysrecs, fphysrecs);

			set_dsk_fdr_cluster(dsk_file->l2_img, &dsk_file->fdr, cluster_index, first_best_block_baseAU, fphysrecs-1);
			cluster_AUlen = (nb_alloc_physrecs + dsk_file->l2_img->AUformat.physrecsperAU - 1) / dsk_file->l2_img->AUformat.physrecsperAU;
			for (i=0; i<cluster_AUlen; i++)
				dsk_file->l2_img->abm[(i+first_best_block_baseAU) >> 3] |= 1 << ((i+first_best_block_baseAU) & 7);

			nb_alloc_physrecs = 0;
		}
		else if (second_best_block_seclen != 0)
		{	/* jeez, we need to fragment it.  We use the largest smaller block to limit fragmentation. */
			fphysrecs += second_best_block_seclen;
			set_UINT16BE(& dsk_file->fdr.fphysrecs, fphysrecs);

			set_dsk_fdr_cluster(dsk_file->l2_img, &dsk_file->fdr, cluster_index, second_best_block_baseAU, fphysrecs-1);
			cluster_AUlen = (second_best_block_seclen + dsk_file->l2_img->AUformat.physrecsperAU - 1) / dsk_file->l2_img->AUformat.physrecsperAU;
			for (i=0; i<cluster_AUlen; i++)
				dsk_file->l2_img->abm[(i+second_best_block_baseAU) >> 3] |= 1 << ((i+second_best_block_baseAU) & 7);

			nb_alloc_physrecs -= second_best_block_seclen;

			cluster_index++;
			if (cluster_index == 76)
				/* that sucks */
				return IMGTOOLERR_NOSPACE;
		}
		else if (search_start != 0)
		{	/* we did not find any free physrec in the data section of the disk */
			search_start = 0;	/* time to fall back to fdr space */
		}
		else
			return IMGTOOLERR_NOSPACE;	/* This should never happen, as we pre-check that there is enough free space */
	}

	return 0;
}

/*
	Extend a file with nb_alloc_physrecs extra physrecs

	win_file: file reference
	nb_alloc_physrecs: number of physical records to allocate
*/
static int win_alloc_file_physrecs(ti99_lvl2_fileref_win *win_file, int nb_alloc_physrecs)
{
	int totAUs = win_file->l2_img->AUformat.totAUs;
	int free_physrecs;
	int fphysrecs;
	int i;
	int cluster_index;
	int num_fphysrec;
	int cur_block_seclen;
	int cluster_baseAU, cluster_AUlen;
	int first_best_block_baseAU = 0, first_best_block_seclen;
	int second_best_block_baseAU = 0, second_best_block_seclen;
	int search_start;
	int errorcode;

	/* compute free space */
	free_physrecs = 0;
	for (i=0; i<totAUs; i++)
	{
		if (! (win_file->l2_img->abm[i >> 3] & (1 << (i & 7))))
			free_physrecs += win_file->l2_img->AUformat.physrecsperAU;
	}

	/* check we have enough free space */
	if (free_physrecs < nb_alloc_physrecs)
		return IMGTOOLERR_NOSPACE;

	/* move to last sibling non-empty FDR */
	while ((get_UINT16BE(win_file->curfdr.nextsibFDR_AU) != 0) &&
				(get_UINT16BE(win_file->curfdr.clusters[53][0]) != 0))
	{
		errorcode = win_goto_next_sibFDR(win_file);
		if (errorcode)
			return errorcode;
	}
	if ((get_UINT16BE(win_file->curfdr.clusters[0][0]) == 0) && (get_UINT16BE(win_file->curfdr.prevsibFDR_AU) != 0))
	{	/* this is annoying: we have found a sibling FDR filled with 0s: rewind
		to last non-empty sibling if applicable */
		errorcode = win_goto_prev_sibFDR(win_file);
		if (errorcode)
			return errorcode;
	}

	/* current number of data physrecs in file */
	fphysrecs = win_file->fphysrecs;

	/* current number of allocated physrecs */
	num_fphysrec = get_win_fdr_cursibFDR_basefphysrec(&win_file->curfdr)
						+ get_UINT16BE(win_file->curfdr.sibFDR_AUlen) * win_file->l2_img->AUformat.physrecsperAU;

	if (num_fphysrec > fphysrecs)
	{	/* some extra space has already been allocated */
		cur_block_seclen = num_fphysrec - fphysrecs;
		if (cur_block_seclen > nb_alloc_physrecs)
			cur_block_seclen = nb_alloc_physrecs;

		fphysrecs += cur_block_seclen;
		win_file->fphysrecs = fphysrecs;
		/* TODO: update eldest FDR fphysrecs field */
		/*set_win_fdr_fphysrecs(& win_file->rootfdr.fphysrecs, fphysrecs);*/
		nb_alloc_physrecs -= cur_block_seclen;
		if (! nb_alloc_physrecs)
			return 0;	/* done */
	}

	/* find last non-empty cluster */
	for (cluster_index=0; (cluster_index<54) && (get_UINT16BE(win_file->curfdr.clusters[cluster_index][0]) != 0); cluster_index++)
		;
	/* if we are dealing with an empty file, we will have (cluster_index == 0)... */
	if (cluster_index != 0)
	{
		cluster_index--;
		/* try to extend last cluster */
		/* point past cluster end */
		cluster_baseAU = get_UINT16BE(win_file->curfdr.clusters[cluster_index][1]) + 1;
		/* count free physrecs after last block */
		cur_block_seclen = 0;
		for (i=cluster_baseAU; (! (win_file->l2_img->abm[i >> 3] & (1 << (i & 7)))) && (cur_block_seclen < nb_alloc_physrecs) && (i < totAUs); i++)
			cur_block_seclen += win_file->l2_img->AUformat.physrecsperAU;
		if (cur_block_seclen)
		{	/* extend last block */
			if (cur_block_seclen > nb_alloc_physrecs)
				cur_block_seclen = nb_alloc_physrecs;

			fphysrecs += cur_block_seclen;
			cluster_AUlen = (cur_block_seclen + win_file->l2_img->AUformat.physrecsperAU - 1) / win_file->l2_img->AUformat.physrecsperAU;
			win_file->fphysrecs = fphysrecs;
			/* TODO: update eldest FDR fphysrecs field */
			/*set_win_fdr_fphysrecs(& win_file->rootfdr.fphysrecs, fphysrecs);*/
			set_UINT16BE(&win_file->curfdr.sibFDR_AUlen,
							get_UINT16BE(win_file->curfdr.sibFDR_AUlen)+cluster_AUlen);
			set_UINT16BE(&win_file->curfdr.clusters[cluster_index][1],
							get_UINT16BE(win_file->curfdr.clusters[cluster_index][1])+cluster_AUlen);
			for (i=0; i<cluster_AUlen; i++)
				win_file->l2_img->abm[(i+cluster_baseAU) >> 3] |= 1 << ((i+cluster_baseAU) & 7);
			nb_alloc_physrecs -= cur_block_seclen;
			if (! nb_alloc_physrecs)
				return 0;	/* done */
		}
		/* now point to first free entry in cluster table */
		cluster_index++;
	}

	search_start = win_file->l2_img->data_offset;	/* initially, search for free space only in data space */
	while (nb_alloc_physrecs)
	{
		/* find smallest data block at least nb_alloc_physrecs in lenght, and largest data block less than nb_alloc_physrecs in lenght */
		first_best_block_seclen = INT_MAX;
		second_best_block_seclen = 0;
		for (i=search_start; i<totAUs; i++)
		{
			if (! (win_file->l2_img->abm[i >> 3] & (1 << (i & 7))))
			{	/* found one free block */
				/* compute its lenght */
				cluster_baseAU = i;
				cur_block_seclen = 0;
				while ((i<totAUs) && (! (win_file->l2_img->abm[i >> 3] & (1 << (i & 7)))))
				{
					cur_block_seclen += win_file->l2_img->AUformat.physrecsperAU;
					i++;
				}
				/* compare to previous best and second-best blocks */
				if ((cur_block_seclen < first_best_block_seclen) && (cur_block_seclen >= nb_alloc_physrecs))
				{
					first_best_block_baseAU = cluster_baseAU;
					first_best_block_seclen = cur_block_seclen;
					if (cur_block_seclen == nb_alloc_physrecs)
						/* no need to search further */
						break;
				}
				else if ((cur_block_seclen > second_best_block_seclen) && (cur_block_seclen < nb_alloc_physrecs))
				{
					second_best_block_baseAU = cluster_baseAU;
					second_best_block_seclen = cur_block_seclen;
				}
			}
		}

		if ((first_best_block_seclen != INT_MAX) || (second_best_block_seclen != 0))
		{
			if (cluster_index == 54)
			{
				/* end of cluster list: go to next sibling FDR */
				if (write_absolute_physrec(& win_file->l2_img->l1_img, win_file->curfdr_aphysrec, &win_file->curfdr))
					return IMGTOOLERR_WRITEERROR;
				if (get_UINT16BE(win_file->curfdr.nextsibFDR_AU) != 0)
				{	/* read next sibling FDR */
					errorcode = win_goto_next_sibFDR(win_file);
					if (errorcode)
						return errorcode;
				}
				else
				{	/* allocate new sibling FDR */
					errorcode = win_alloc_sibFDR(win_file);
					if (errorcode)
						return errorcode;
				}
				cluster_index = 0;
			}
		}

		if (first_best_block_seclen != INT_MAX)
		{	/* found one contiguous block which can hold it all */
			fphysrecs += nb_alloc_physrecs;
			cluster_AUlen = (nb_alloc_physrecs + win_file->l2_img->AUformat.physrecsperAU - 1) / win_file->l2_img->AUformat.physrecsperAU;
			win_file->fphysrecs = fphysrecs;
			/* TODO: update eldest FDR fphysrecs field */
			/*set_win_fdr_fphysrecs(& win_file->rootfdr.fphysrecs, fphysrecs);*/
			set_UINT16BE(&win_file->curfdr.sibFDR_AUlen,
								get_UINT16BE(win_file->curfdr.sibFDR_AUlen)+cluster_AUlen);
			set_UINT16BE(&win_file->curfdr.clusters[cluster_index][0], first_best_block_baseAU);
			set_UINT16BE(&win_file->curfdr.clusters[cluster_index][1],
								first_best_block_baseAU+cluster_AUlen-1);

			for (i=0; i<cluster_AUlen; i++)
				win_file->l2_img->abm[(i+first_best_block_baseAU) >> 3] |= 1 << ((i+first_best_block_baseAU) & 7);

			nb_alloc_physrecs = 0;
		}
		else if (second_best_block_seclen != 0)
		{	/* jeez, we need to fragment it.  We use the largest smaller block to limit fragmentation. */
			fphysrecs += second_best_block_seclen;
			cluster_AUlen = (second_best_block_seclen + win_file->l2_img->AUformat.physrecsperAU - 1) / win_file->l2_img->AUformat.physrecsperAU;
			win_file->fphysrecs = fphysrecs;
			/* TODO: update eldest FDR fphysrecs field */
			/*set_win_fdr_fphysrecs(& win_file->rootfdr.fphysrecs, fphysrecs);*/
			set_UINT16BE(&win_file->curfdr.sibFDR_AUlen,
								get_UINT16BE(win_file->curfdr.sibFDR_AUlen)+cluster_AUlen);
			set_UINT16BE(&win_file->curfdr.clusters[cluster_index][0], second_best_block_baseAU);
			set_UINT16BE(&win_file->curfdr.clusters[cluster_index][1],
								second_best_block_baseAU+cluster_AUlen-1);

			for (i=0; i<cluster_AUlen; i++)
				win_file->l2_img->abm[(i+second_best_block_baseAU) >> 3] |= 1 << ((i+second_best_block_baseAU) & 7);

			nb_alloc_physrecs -= second_best_block_seclen;

			/* now point to first free entry in cluster table */
			cluster_index++;
		}
		else if (search_start != 0)
		{	/* we did not find any free physrec in the data section of the disk */
			search_start = 0;	/* time to fall back to fdr space */
		}
		else
			return IMGTOOLERR_NOSPACE;	/* This should never happen, as we pre-check that there is enough free space */
	}

	return 0;
}

/*
	Allocate a new (empty) file
*/
static int new_file_lvl2_dsk(ti99_lvl2_imgref *l2_img, int parent_ref, char filename[10], ti99_lvl2_fileref *l2_file)
{
	ti99_catalog *catalog = &l2_img->u.dsk.catalogs[parent_ref];
	unsigned fdr_AU, fdr_aphysrec;
	int catalog_index, i;
	int reply = 0;
	int errorcode;


	if (catalog->num_files >= 127)
		/* if num_files == 128, catalog is full */
		/* if num_files == 127, catalog is not full, but we don't want to write
		a 128th entry for compatibility with some existing DSRs that detect the
		end of the FDIR array with a 0 entry (and do not check that the index
		has not reached 128) */
		return IMGTOOLERR_NOSPACE;

	/* find insertion point in catalog */
	for (i=0; (i < catalog->num_files) && ((reply = memcmp(catalog->files[i].name, filename, 10)) < 0); i++)
		;

	if ((i<catalog->num_files) && (reply == 0))
		/* file already exists */
		return IMGTOOLERR_BADFILENAME;
	else
	{
		/* otherwise insert new entry */
		catalog_index = i;
		errorcode = alloc_fdr_AU(l2_img, &fdr_AU);
		if (errorcode)
			return errorcode;
		fdr_aphysrec = fdr_AU * l2_img->AUformat.physrecsperAU;

		/* shift catalog entries until the insertion point */
		for (i=catalog->num_files; i>catalog_index; i--)
			catalog->files[i] = catalog->files[i-1];

		/* write new catalog entry */
		catalog->files[catalog_index].fdr_ptr = fdr_aphysrec;
		memcpy(catalog->files[catalog_index].name, filename, 10);

		/* update catalog len */
		catalog->num_files++;
	}

	/* set up file handle */
	l2_file->type = L2F_DSK;
	l2_file->u.dsk.l2_img = l2_img;
	l2_file->u.dsk.fdr_aphysrec = fdr_aphysrec;
	memset(&l2_file->u.dsk.fdr, 0, sizeof(l2_file->u.dsk.fdr));
	memcpy(l2_file->u.dsk.fdr.name, filename, 10);

	return 0;
}

/*
	Allocate a new (empty) file
*/
static int new_file_lvl2_win(ti99_lvl2_imgref *l2_img, ti99_catalog *parent_catalog, char filename[10], ti99_lvl2_fileref *l2_file)
{
	unsigned fdr_AU;
	int catalog_index, i;
	int reply = 0;
	int errorcode;


	if (parent_catalog->num_files >= 127)
		/* if num_files == 127, catalog is full */
		return IMGTOOLERR_NOSPACE;

	/* find insertion point in catalog */
	for (i=0; (i < parent_catalog->num_files) && ((reply = memcmp(parent_catalog->files[i].name, filename, 10)) < 0); i++)
		;

	if ((i<parent_catalog->num_files) && (reply == 0))
		/* file already exists */
		return IMGTOOLERR_BADFILENAME;
	else
	{
		/* otherwise insert new entry */
		catalog_index = i;
		errorcode = alloc_fdr_AU(l2_img, &fdr_AU);
		if (errorcode)
			return errorcode;

		/* shift catalog entries until the insertion point */
		for (i=parent_catalog->num_files; i>catalog_index; i--)
			parent_catalog->files[i] = parent_catalog->files[i-1];

		/* write new catalog entry */
		parent_catalog->files[catalog_index].fdr_ptr = fdr_AU;
		memcpy(parent_catalog->files[catalog_index].name, filename, 10);

		/* update catalog len */
		parent_catalog->num_files++;
	}

	/* set up file handle */
	l2_file->type = L2F_WIN;
	l2_file->u.win.l2_img = l2_img;
	l2_file->u.win.fphysrecs = 0;
	l2_file->u.win.eldestfdr_aphysrec = fdr_AU * l2_img->AUformat.physrecsperAU;
	l2_file->u.win.curfdr_aphysrec = l2_file->u.win.eldestfdr_aphysrec;
	memset(&l2_file->u.win.curfdr, 0, sizeof(l2_file->u.win.curfdr));
	memcpy(l2_file->u.win.curfdr.name, filename, 10);

	return 0;
}

/*
	Allocate a new (empty) file
*/
static int new_file_lvl2_tifiles(imgtool_stream *file_handle, ti99_lvl2_fileref *l2_file)
{
	/* set up file handle */
	l2_file->type = L2F_TIFILES;
	l2_file->u.tifiles.file_handle = file_handle;
	memset(&l2_file->u.tifiles.hdr, 0, sizeof(l2_file->u.tifiles.hdr));
	l2_file->u.tifiles.hdr.tifiles[0] = '\7';
	l2_file->u.tifiles.hdr.tifiles[1] = 'T';
	l2_file->u.tifiles.hdr.tifiles[2] = 'I';
	l2_file->u.tifiles.hdr.tifiles[3] = 'F';
	l2_file->u.tifiles.hdr.tifiles[4] = 'I';
	l2_file->u.tifiles.hdr.tifiles[5] = 'L';
	l2_file->u.tifiles.hdr.tifiles[6] = 'E';
	l2_file->u.tifiles.hdr.tifiles[7] = 'S';

	return 0;
}

/*
	Open an existing file on a floppy image

	l2_img: level 2 image the file is located on
	fpath: access path to the file
	file: set up if open is successful
*/
static int open_file_lvl2_dsk(ti99_lvl2_imgref *l2_img, const char *fpath, ti99_lvl2_fileref *l2_file)
{
	int parent_ref, is_dir, catalog_index;
	int reply;


	reply = dsk_find_catalog_entry(l2_img, fpath, NULL, &parent_ref, &is_dir, &catalog_index);
	if (reply)
		return reply;

	if (is_dir)
		/* this is not a file */
		return IMGTOOLERR_BADFILENAME;

	l2_file->type = L2F_DSK;
	l2_file->u.dsk.l2_img = l2_img;
	l2_file->u.dsk.fdr_aphysrec = l2_img->u.dsk.catalogs[parent_ref].files[catalog_index].fdr_ptr;
	if (read_absolute_physrec(& l2_img->l1_img, l2_file->u.dsk.fdr_aphysrec, &l2_file->u.dsk.fdr))
		return IMGTOOLERR_READERROR;

	return 0;
}

/*
	Open an existing file on a harddisk image

	l2_img: level 2 image the file is located on
	fpath: access path to the file
	file: set up if open is successful
*/
static int open_file_lvl2_win(ti99_lvl2_imgref *l2_img, const char *fpath, ti99_lvl2_fileref *l2_file)
{
	int parent_ref, is_dir, catalog_index;
	ti99_catalog catalog;
	int reply;

	reply = win_find_catalog_entry(l2_img, fpath, NULL, &parent_ref, &catalog, &is_dir, &catalog_index);
	if (reply)
		return reply;

	if (is_dir)
		/* this is not a file */
		return IMGTOOLERR_BADFILENAME;

	l2_file->type = L2F_WIN;
	l2_file->u.win.l2_img = l2_img;
	l2_file->u.win.eldestfdr_aphysrec = catalog.files[catalog_index].fdr_ptr * l2_img->AUformat.physrecsperAU;
	l2_file->u.win.curfdr_aphysrec = l2_file->u.win.eldestfdr_aphysrec;
	if (read_absolute_physrec(& l2_img->l1_img, l2_file->u.win.curfdr_aphysrec, &l2_file->u.win.curfdr))
		return IMGTOOLERR_READERROR;
	l2_file->u.win.fphysrecs = get_win_fdr_fphysrecs(&l2_file->u.win.curfdr);

	/* check integrity of FDR sibling chain */
	/* note that as we check that the back chain is consistent with the forward
	chain, we will also detect any cycle in the sibling chain, so we do not
	need to check against them explicitely */
	if (get_UINT16BE(l2_file->u.win.curfdr.prevsibFDR_AU) != 0)
		return IMGTOOLERR_CORRUPTIMAGE;

	{
		int i, pastendoflist_flag;
		unsigned cur_fphysrec, sibFDR_AUlen;
		win_fdr *cur_fdr, fdr_buf;
		unsigned curfdr_aphysrec, prevfdr_aphysrec;

		cur_fphysrec = 0;
		pastendoflist_flag = 0;
		cur_fdr = &l2_file->u.win.curfdr;
		curfdr_aphysrec = l2_file->u.win.eldestfdr_aphysrec;

		while (1)
		{
			sibFDR_AUlen = 0;
			i=0;
			if (! pastendoflist_flag)
			{
				/* compute number of allocated AUs and check number of AUs */
				for (; i<54; i++)
				{
					if (get_UINT16BE(cur_fdr->clusters[i][0]) == 0)
					{
						pastendoflist_flag = TRUE;
						break;
					}
					sibFDR_AUlen += get_UINT16BE(cur_fdr->clusters[i][1])
									- get_UINT16BE(cur_fdr->clusters[i][0])
									+ 1;
				}
			}
			/* clear remainder of cluster table */
			for (; i<54; i++)
			{
				/*set_UINT16BE(&cur_fdr->clusters[i][0], 0);
				set_UINT16BE(&cur_fdr->clusters[i][1], 0);*/
				if ((get_UINT16BE(cur_fdr->clusters[i][0]) != 0) || (get_UINT16BE(cur_fdr->clusters[i][1]) != 0))
					return IMGTOOLERR_CORRUPTIMAGE;
			}

			/* check sibFDR_AUlen field */
			if (get_UINT16BE(cur_fdr->sibFDR_AUlen) != sibFDR_AUlen)
				return IMGTOOLERR_CORRUPTIMAGE;

			/* update current file physrec position to point to end of sibling FDR */
			cur_fphysrec += sibFDR_AUlen * l2_file->u.win.l2_img->AUformat.physrecsperAU;

			/* exit loop if end of sibling chain */
			if (! get_UINT16BE(cur_fdr->nextsibFDR_AU))
				break;

			/* otherwise read next FDR */
			if (get_UINT16BE(cur_fdr->nextsibFDR_AU) >= l2_file->u.win.l2_img->AUformat.totAUs)
				return IMGTOOLERR_CORRUPTIMAGE;

			prevfdr_aphysrec = curfdr_aphysrec;
			curfdr_aphysrec = get_win_fdr_nextsibFDR_aphysrec(l2_file->u.win.l2_img, cur_fdr);
			if (read_absolute_physrec(& l2_file->u.win.l2_img->l1_img, curfdr_aphysrec, &fdr_buf))
				return IMGTOOLERR_READERROR;
			cur_fdr = &fdr_buf;

			/* check that back chaining is consistent with forward chaining */
			if (get_win_fdr_prevsibFDR_aphysrec(l2_file->u.win.l2_img, &fdr_buf) != prevfdr_aphysrec)
				return IMGTOOLERR_CORRUPTIMAGE;
			/*  check fphysrecs field */
			if (get_win_fdr_fphysrecs(&fdr_buf) != cur_fphysrec)
				return IMGTOOLERR_CORRUPTIMAGE;

			/* check consistency of informative fields (name, record format, flags, etc) */
			if (memcmp(fdr_buf.name, l2_file->u.win.curfdr.name, 10)
					|| (get_UINT16BE(fdr_buf.xreclen) != get_UINT16BE(l2_file->u.win.curfdr.xreclen))
					|| (fdr_buf.flags != l2_file->u.win.curfdr.flags)
					|| (fdr_buf.recsperphysrec != l2_file->u.win.curfdr.recsperphysrec)
					|| (fdr_buf.eof != l2_file->u.win.curfdr.eof)
					|| (fdr_buf.reclen != l2_file->u.win.curfdr.reclen)
					|| (get_UINT16LE(fdr_buf.fixrecs_LSW) != get_UINT16LE(l2_file->u.win.curfdr.fixrecs_LSW))
					|| memcmp(&fdr_buf.creation, &l2_file->u.win.curfdr.creation, 4)
					|| memcmp(&fdr_buf.update, &l2_file->u.win.curfdr.update, 4)
					/*|| memcmp(fdr_buf.id, l2_file->u.win.curfdr.id, 2)*/
					|| (get_UINT16BE(fdr_buf.parent_FDIR_AU) != get_UINT16BE(l2_file->u.win.curfdr.parent_FDIR_AU))
					|| ((fdr_buf.xinfo_MSB & 0xf) != (l2_file->u.win.curfdr.xinfo_MSB & 0xf)))
				return IMGTOOLERR_CORRUPTIMAGE;
		}
		if (cur_fphysrec < l2_file->u.win.fphysrecs)
			return IMGTOOLERR_CORRUPTIMAGE;
	}

	return 0;
}

/*
	Open an existing file in TIFILES format
*/
static int open_file_lvl2_tifiles(imgtool_stream *file_handle, ti99_lvl2_fileref *l2_file)
{
	/* set up file handle */
	l2_file->type = L2F_TIFILES;
	l2_file->u.tifiles.file_handle = file_handle;

	/* seek to header */
	if (stream_seek(l2_file->u.tifiles.file_handle, 0, SEEK_SET))
		return IMGTOOLERR_READERROR;
	/* read it */
	if (stream_read(l2_file->u.tifiles.file_handle, &l2_file->u.tifiles.hdr, sizeof(l2_file->u.tifiles.hdr)) != sizeof(l2_file->u.tifiles.hdr))
		return IMGTOOLERR_READERROR;

	return 0;
}

/*
	compute the aphysrec address for a given file physical record (fphysrec)

	l2_img: image where the file is located
*/
static int dsk_fphysrec_to_aphysrec(ti99_lvl2_fileref_dsk *dsk_file, unsigned fphysrec, unsigned *aphysrec)
{
	int cluster_index;
	int cluster_firstfphysrec, cluster_lastfphysrec;
	int cluster_baseaphysrec;


	/* check parameter */
	if (fphysrec >= get_UINT16BE(dsk_file->fdr.fphysrecs))
		return IMGTOOLERR_UNEXPECTED;


	/* search for the cluster in the data chain pointers array */
	cluster_firstfphysrec = 0;
	for (cluster_index=0; cluster_index<76; cluster_index++)
	{
		/* read curent file block table entry */
		cluster_lastfphysrec = get_dsk_fdr_cluster_lastfphysrec(&dsk_file->fdr, cluster_index);
		if (cluster_lastfphysrec >= fphysrec)
			break;
		cluster_firstfphysrec = cluster_lastfphysrec+1;
	}
	if (cluster_index == 76)
		/* if not found, the file is corrupt */
		return IMGTOOLERR_CORRUPTIMAGE;

	/* read base aphysrec address for this cluster */
	cluster_baseaphysrec = get_dsk_fdr_cluster_baseaphysrec(dsk_file->l2_img, &dsk_file->fdr, cluster_index);
	/* return absolute physrec address */
	*aphysrec = cluster_baseaphysrec + (fphysrec - cluster_firstfphysrec);
	return 0;
}

/*
	compute the aphysrec address for a given file physical record (fphysrec)

	l2_img: image where the file is located
*/
static int win_fphysrec_to_aphysrec(ti99_lvl2_fileref_win *win_file, unsigned fphysrec, unsigned *aphysrec)
{
	int cluster_index;
	int cluster_firstfphysrec, cluster_lastfphysrec;
	int cluster_baseaphysrec;
	int errorcode;


	/* check parameter */
	if (fphysrec >= win_file->fphysrecs)
		return IMGTOOLERR_UNEXPECTED;

	/* look for correct sibling */
	if (fphysrec < get_win_fdr_cursibFDR_basefphysrec(& win_file->curfdr))
	{
		while (fphysrec < get_win_fdr_cursibFDR_basefphysrec(& win_file->curfdr))
		{
			if (get_UINT16BE(win_file->curfdr.prevsibFDR_AU) == 0)
				return IMGTOOLERR_CORRUPTIMAGE;
			errorcode = win_goto_prev_sibFDR(win_file);
			if (errorcode)
				return errorcode;
		}
	}
	else /*if (fphysrec >= get_win_fdr_cursibFDR_basefphysrec(& dsk_file->curfdr))*/
	{
		while (fphysrec >= (get_win_fdr_cursibFDR_basefphysrec(& win_file->curfdr)
								+ get_UINT16BE(win_file->curfdr.sibFDR_AUlen) * win_file->l2_img->AUformat.physrecsperAU))
		{
			if (get_UINT16BE(win_file->curfdr.nextsibFDR_AU) == 0)
				return IMGTOOLERR_CORRUPTIMAGE;
			errorcode = win_goto_next_sibFDR(win_file);
			if (errorcode)
				return errorcode;
		}
	}


	/* search for the cluster in the data chain pointers array */
	cluster_firstfphysrec = get_win_fdr_cursibFDR_basefphysrec(& win_file->curfdr);
	for (cluster_index = 0; cluster_index<54; cluster_index++)
	{
		cluster_lastfphysrec = cluster_firstfphysrec
									+ (get_UINT16BE(win_file->curfdr.clusters[cluster_index][1])
											- get_UINT16BE(win_file->curfdr.clusters[cluster_index][0])
											+ 1)
										* win_file->l2_img->AUformat.physrecsperAU;
		if (fphysrec < cluster_lastfphysrec)
			break;

		cluster_firstfphysrec = cluster_lastfphysrec;
	}

	if (cluster_index == 54)
		return IMGTOOLERR_CORRUPTIMAGE;


	/* read base aphysrec address for this cluster */
	cluster_baseaphysrec = get_UINT16BE(win_file->curfdr.clusters[cluster_index][0]) * win_file->l2_img->AUformat.physrecsperAU;
	/* return absolute physrec address */
	*aphysrec = cluster_baseaphysrec + (fphysrec - cluster_firstfphysrec);
	return 0;
}

/*
	read a 256-byte physical record from a file
*/
static int read_file_physrec(ti99_lvl2_fileref *l2_file, unsigned fphysrec, void *dest)
{
	int errorcode;
	unsigned aphysrec;

	switch (l2_file->type)
	{
	case L2F_DSK:
		/* compute absolute physrec address */
		errorcode = dsk_fphysrec_to_aphysrec(&l2_file->u.dsk, fphysrec, &aphysrec);
		if (errorcode)
			return errorcode;
		/* read physrec */
		if (read_absolute_physrec(& l2_file->u.dsk.l2_img->l1_img, aphysrec, dest))
			return IMGTOOLERR_READERROR;
		break;

	case L2F_WIN:
		/* compute absolute physrec address */
		errorcode = win_fphysrec_to_aphysrec(&l2_file->u.win, fphysrec, &aphysrec);
		if (errorcode)
			return errorcode;
		/* read physrec */
		if (read_absolute_physrec(& l2_file->u.win.l2_img->l1_img, aphysrec, dest))
			return IMGTOOLERR_READERROR;
		break;

	case L2F_TIFILES:
		/* seek to physrec */
		if (stream_seek(l2_file->u.tifiles.file_handle, 128+256*fphysrec, SEEK_SET))
			return IMGTOOLERR_READERROR;
		/* read it */
		if (stream_read(l2_file->u.tifiles.file_handle, dest, 256) != 256)
			return IMGTOOLERR_READERROR;
		break;
	}

	return 0;
}

/*
	read a 256-byte physical record from a file
*/
static int write_file_physrec(ti99_lvl2_fileref *l2_file, unsigned fphysrec, const void *src)
{
	int errorcode;
	unsigned aphysrec;

	switch (l2_file->type)
	{
	case L2F_DSK:
		/* compute absolute physrec address */
		errorcode = dsk_fphysrec_to_aphysrec(&l2_file->u.dsk, fphysrec, &aphysrec);
		if (errorcode)
			return errorcode;
		/* write physrec */
		if (write_absolute_physrec(& l2_file->u.dsk.l2_img->l1_img, aphysrec, src))
			return IMGTOOLERR_WRITEERROR;
		break;

	case L2F_WIN:
		/* compute absolute physrec address */
		errorcode = win_fphysrec_to_aphysrec(&l2_file->u.win, fphysrec, &aphysrec);
		if (errorcode)
			return errorcode;
		/* write physrec */
		if (write_absolute_physrec(& l2_file->u.win.l2_img->l1_img, aphysrec, src))
			return IMGTOOLERR_WRITEERROR;
		break;

	case L2F_TIFILES:
		/* seek to physrec */
		if (stream_seek(l2_file->u.tifiles.file_handle, 128+256*fphysrec, SEEK_SET))
			return IMGTOOLERR_WRITEERROR;
		/* write it */
		if (stream_write(l2_file->u.tifiles.file_handle, src, 256) != 256)
			return IMGTOOLERR_WRITEERROR;
		break;
	}

	return 0;
}

/*
	Write a field in every fdr record associated to a file
*/
/*static int set_win_fdr_field(ti99_lvl2_fileref *l2_file, size_t offset, size_t size, void *data)
{
	win_fdr fdr_buf;
	unsigned fdr_aphysrec;
	int errorcode = 0;

	for (fdr_aphysrec = l2_file->u.win.eldestfdr_aphysrec;
			fdr_aphysrec && ((errorcode = (read_absolute_physrec(&l2_file->u.win.l2_img->l1_img, fdr_aphysrec, &fdr_buf) ? IMGTOOLERR_READERROR : 0)) == 0);
			fdr_aphysrec = get_win_fdr_nextsibFDR_physrec(l2_file->u.win.l2_img, &fdr_buf))
	{
		memcpy(((UINT8 *) &fdr_buf) + offset, data, size);
		if (write_absolute_physrec(&l2_file->u.win.l2_img->l1_img, fdr_aphysrec, &fdr_buf))
		{
			errorcode = IMGTOOLERR_WRITEERROR;
			break;
		}
	}

	return errorcode;
}*/

static UINT8 get_file_flags(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = l2_file->u.dsk.fdr.flags;
		break;

	case L2F_WIN:
		reply = l2_file->u.win.curfdr.flags;
		break;

	case L2F_TIFILES:
		reply = l2_file->u.tifiles.hdr.flags;
		break;
	}

	return reply;
}

static void set_file_flags(ti99_lvl2_fileref *l2_file, UINT8 data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		l2_file->u.dsk.fdr.flags = data;
		break;

	case L2F_WIN:
		l2_file->u.win.curfdr.flags = data;
		break;

	case L2F_TIFILES:
		l2_file->u.tifiles.hdr.flags = data;
		break;
	}
}

static UINT8 get_file_recsperphysrec(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = l2_file->u.dsk.fdr.recsperphysrec;
		break;

	case L2F_WIN:
		reply = l2_file->u.win.curfdr.recsperphysrec;
		break;

	case L2F_TIFILES:
		reply = l2_file->u.tifiles.hdr.recsperphysrec;
		break;
	}

	return reply;
}

static void set_file_recsperphysrec(ti99_lvl2_fileref *l2_file, UINT8 data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		l2_file->u.dsk.fdr.recsperphysrec = data;
		break;

	case L2F_WIN:
		l2_file->u.win.curfdr.recsperphysrec = data;
		break;

	case L2F_TIFILES:
		l2_file->u.tifiles.hdr.recsperphysrec = data;
		break;
	}
}

static unsigned get_file_fphysrecs(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = get_UINT16BE(l2_file->u.dsk.fdr.fphysrecs);
		break;

	case L2F_WIN:
		reply = l2_file->u.win.fphysrecs;
		break;

	case L2F_TIFILES:
		reply = get_UINT16BE(l2_file->u.tifiles.hdr.fphysrecs);
		break;
	}

	return reply;
}

static int set_file_fphysrecs(ti99_lvl2_fileref *l2_file, unsigned data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		if (data >= 65536)
			return IMGTOOLERR_UNIMPLEMENTED;
		set_UINT16BE(&l2_file->u.dsk.fdr.fphysrecs, data);
		break;

	case L2F_WIN:
		l2_file->u.win.fphysrecs = data;
		break;

	case L2F_TIFILES:
		if (data >= 65536)
			return IMGTOOLERR_UNIMPLEMENTED;
		set_UINT16BE(&l2_file->u.tifiles.hdr.fphysrecs, data);
		break;
	}

	return 0;
}

static UINT8 get_file_eof(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = l2_file->u.dsk.fdr.eof;
		break;

	case L2F_WIN:
		reply = l2_file->u.win.curfdr.eof;
		break;

	case L2F_TIFILES:
		reply = l2_file->u.tifiles.hdr.eof;
		break;
	}

	return reply;
}

static void set_file_eof(ti99_lvl2_fileref *l2_file, UINT8 data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		l2_file->u.dsk.fdr.eof = data;
		break;

	case L2F_WIN:
		l2_file->u.win.curfdr.eof = data;
		break;

	case L2F_TIFILES:
		l2_file->u.tifiles.hdr.eof = data;
		break;
	}
}

static UINT16 get_file_reclen(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = l2_file->u.dsk.fdr.reclen;
		if ((reply == 0) && (! (l2_file->u.dsk.fdr.flags & (fdr99_f_program /*| fdr99_f_var*/))))
			reply = get_UINT16BE(l2_file->u.dsk.fdr.xreclen);
		break;

	case L2F_WIN:
		reply = l2_file->u.win.curfdr.reclen;
		if ((reply == 0) && (! (l2_file->u.win.curfdr.flags & (fdr99_f_program /*| fdr99_f_var*/))))
			reply = get_UINT16BE(l2_file->u.win.curfdr.xreclen);
		break;

	case L2F_TIFILES:
		reply = l2_file->u.tifiles.hdr.reclen;
		break;
	}

	return reply;
}

static int set_file_reclen(ti99_lvl2_fileref *l2_file, UINT16 data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		if (data < 256)
		{
			l2_file->u.dsk.fdr.reclen = data;
			set_UINT16BE(&l2_file->u.dsk.fdr.xreclen, 0);
		}
		else
		{
			l2_file->u.dsk.fdr.reclen = 0;
			set_UINT16BE(&l2_file->u.dsk.fdr.xreclen, data);
		}
		break;

	case L2F_WIN:
		if (data < 256)
		{
			l2_file->u.win.curfdr.reclen = data;
			set_UINT16BE(&l2_file->u.win.curfdr.xreclen, 0);
		}
		else
		{
			l2_file->u.win.curfdr.reclen = 0;
			set_UINT16BE(&l2_file->u.win.curfdr.xreclen, data);
		}
		break;

	case L2F_TIFILES:
		if (data >= 256)
			return IMGTOOLERR_UNIMPLEMENTED;
		l2_file->u.tifiles.hdr.reclen = data;
		break;
	}

	return 0;
}

static unsigned get_file_fixrecs(ti99_lvl2_fileref *l2_file)
{
	int reply = 0;

	switch (l2_file->type)
	{
	case L2F_DSK:
		reply = get_UINT16LE(l2_file->u.dsk.fdr.fixrecs);
		break;

	case L2F_WIN:
		reply = get_win_fdr_fixrecs(&l2_file->u.win.curfdr);
		break;

	case L2F_TIFILES:
		reply = get_UINT16BE(l2_file->u.tifiles.hdr.fixrecs);
		break;
	}

	return reply;
}

static int set_file_fixrecs(ti99_lvl2_fileref *l2_file, unsigned data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		if (data >= 65536)
			return IMGTOOLERR_UNIMPLEMENTED;
		set_UINT16LE(&l2_file->u.dsk.fdr.fixrecs, data);
		break;

	case L2F_WIN:
		set_win_fdr_fixrecs(&l2_file->u.win.curfdr, data);
		break;

	case L2F_TIFILES:
		if (data >= 65536)
			return IMGTOOLERR_UNIMPLEMENTED;
		set_UINT16BE(&l2_file->u.tifiles.hdr.fixrecs, data);
		break;
	}

	return 0;
}

static void get_file_creation_date(ti99_lvl2_fileref *l2_file, ti99_date_time *reply)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		*reply = l2_file->u.dsk.fdr.creation;
		break;

	case L2F_WIN:
		*reply = l2_file->u.win.curfdr.creation;
		break;

	case L2F_TIFILES:
		memset(reply, 0, sizeof(*reply));
		break;
	}
}

static void set_file_creation_date(ti99_lvl2_fileref *l2_file, ti99_date_time data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		l2_file->u.dsk.fdr.creation = data;
		break;

	case L2F_WIN:
		l2_file->u.win.curfdr.creation = data;
		break;

	case L2F_TIFILES:
		break;
	}
}

static void get_file_update_date(ti99_lvl2_fileref *l2_file, ti99_date_time *reply)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		*reply = l2_file->u.dsk.fdr.update;
		break;

	case L2F_WIN:
		*reply = l2_file->u.win.curfdr.update;
		break;

	case L2F_TIFILES:
		memset(reply, 0, sizeof(*reply));
		break;
	}
}

static void set_file_update_date(ti99_lvl2_fileref *l2_file, ti99_date_time data)
{
	switch (l2_file->type)
	{
	case L2F_DSK:
		l2_file->u.dsk.fdr.update = data;
		break;

	case L2F_WIN:
		l2_file->u.win.curfdr.update = data;
		break;

	case L2F_TIFILES:
		break;
	}
}

static void current_date_time(ti99_date_time *reply)
{
	/* All these functions should be ANSI */
	time_t cur_time = time(NULL);
	struct tm expanded_time = *localtime(& cur_time);

	reply->time_MSB = (expanded_time.tm_hour << 3) | (expanded_time.tm_min >> 3);
	reply->time_LSB = (expanded_time.tm_min << 5) | (expanded_time.tm_sec >> 1);
	reply->date_MSB = ((expanded_time.tm_year % 100) << 1) | ((expanded_time.tm_mon+1) >> 3);
	reply->date_LSB = ((expanded_time.tm_mon+1) << 5) | expanded_time.tm_mday;
}

#if 0
#pragma mark -
#pragma mark LEVEL 3 DISK ROUTINES
#endif

/*
	Level 3 implements files as a succession of logical records.

	There are three types of files:
	* program files that are not implemented at level 3 (no logical record)
	* files with fixed-size records (random-access files)
	* files with variable-size records (sequential-access)
*/

typedef struct ti99_lvl3_fileref
{
	ti99_lvl2_fileref l2_file;

	int cur_log_rec;
	int cur_phys_rec;
	int cur_pos_in_phys_rec;
} ti99_lvl3_fileref;

/*
	Open a file on level 3.

	To open a file on level 3, you must open (or create) the file on level 2,
	then pass the file reference to open_file_lvl3.
*/
static int open_file_lvl3(ti99_lvl3_fileref *l3_file)
{
	l3_file->cur_log_rec = 0;
	l3_file->cur_phys_rec = 0;
	l3_file->cur_pos_in_phys_rec = 0;

	/*if ()*/

	return 0;
}

/*
	Test a file for EOF
*/
static int is_eof(ti99_lvl3_fileref *l3_file)
{
	int flags = get_file_flags(&l3_file->l2_file);
	int fphysrecs = get_file_fphysrecs(&l3_file->l2_file);
	int fdr_eof = get_file_eof(&l3_file->l2_file);

	if (flags & fdr99_f_var)
	{
		return (l3_file->cur_phys_rec >= fphysrecs);
	}
	else
	{
		return ((l3_file->cur_phys_rec >= fphysrecs)
				|| ((l3_file->cur_phys_rec == (fphysrecs-1))
					&& (l3_file->cur_pos_in_phys_rec >= (fdr_eof ? fdr_eof : 256))));
	}
}

/*
	Read next record from a file
*/
static int read_next_record(ti99_lvl3_fileref *l3_file, void *dest, int *out_reclen)
{
	int errorcode;
	UINT8 physrec_buf[256];
	int reclen;
	int flags = get_file_flags(&l3_file->l2_file);
	int fphysrecs = get_file_fphysrecs(&l3_file->l2_file);
	int fdr_eof = get_file_eof(&l3_file->l2_file);

	if (flags & fdr99_f_program)
	{
		/* program files have no level-3 record */
		return IMGTOOLERR_UNEXPECTED;
	}
	else if (flags & fdr99_f_var)
	{
		/* variable-lenght records */
		if (is_eof(l3_file))
			return IMGTOOLERR_UNEXPECTED;
		errorcode = read_file_physrec(&l3_file->l2_file, l3_file->cur_phys_rec, physrec_buf);
		if (errorcode)
			return errorcode;
		/* read reclen */
		reclen = physrec_buf[l3_file->cur_pos_in_phys_rec];
		/* check integrity */
		if ((reclen == 0xff) || (reclen > get_file_reclen(&l3_file->l2_file))
				|| ((l3_file->cur_pos_in_phys_rec + 1 + reclen) > 256))
			return IMGTOOLERR_CORRUPTIMAGE;
		/* copy to buffer */
		memcpy(dest, physrec_buf + l3_file->cur_pos_in_phys_rec + 1, reclen);
		l3_file->cur_pos_in_phys_rec += reclen + 1;
		/* skip to next physrec if needed */
		if ((l3_file->cur_pos_in_phys_rec == 256)
				|| (physrec_buf[l3_file->cur_pos_in_phys_rec] == 0xff))
		{
			l3_file->cur_pos_in_phys_rec = 0;
			l3_file->cur_phys_rec++;
		}
		(* out_reclen) = reclen;
	}
	else
	{
		/* fixed len records */
		reclen = get_file_reclen(&l3_file->l2_file);
		if (is_eof(l3_file))
			return IMGTOOLERR_UNEXPECTED;
		if ((l3_file->cur_pos_in_phys_rec + reclen) > 256)
		{
			l3_file->cur_pos_in_phys_rec = 0;
			l3_file->cur_phys_rec++;
		}
		if ((l3_file->cur_phys_rec >= fphysrecs)
				|| ((l3_file->cur_phys_rec == (fphysrecs-1))
					&& ((l3_file->cur_pos_in_phys_rec + reclen) >= (fdr_eof ? fdr_eof : 256))))
			return IMGTOOLERR_CORRUPTIMAGE;
		errorcode = read_file_physrec(&l3_file->l2_file, l3_file->cur_phys_rec, physrec_buf);
		if (errorcode)
			return errorcode;
		memcpy(dest, physrec_buf + l3_file->cur_pos_in_phys_rec, reclen);
		l3_file->cur_pos_in_phys_rec += reclen;
		if (l3_file->cur_pos_in_phys_rec == 256)
		{
			l3_file->cur_pos_in_phys_rec = 0;
			l3_file->cur_phys_rec++;
		}
		(* out_reclen) = reclen;
	}

	return 0;
}

#if 0
#pragma mark -
#pragma mark IMGTOOL MODULE IMPLEMENTATION
#endif

/*
	ti99 catalog iterator, used when imgtool reads the catalog
*/
typedef struct dsk_iterator
{
	ti99_lvl2_imgref *image;
	int level;
	int listing_subdirs;		/* true if we are listing subdirectories at current level */
	int index[2];				/* current index in the disk catalog */
	ti99_catalog *cur_catalog;	/* current catalog */
} dsk_iterator;

typedef struct win_iterator
{
	ti99_lvl2_imgref *image;
	int level;
	int listing_subdirs;		/* true if we are listing subdirectories at current level */
	int index[MAX_DIR_LEVEL];	/* current index in the disk catalog */
	ti99_catalog catalog[MAX_DIR_LEVEL];	/* current catalog */
} win_iterator;


static imgtoolerr_t dsk_image_init_mess(imgtool_image *image, imgtool_stream *f);
static imgtoolerr_t dsk_image_init_v9t9(imgtool_image *image, imgtool_stream *f);
static imgtoolerr_t dsk_image_init_pc99_fm(imgtool_image *image, imgtool_stream *f);
static imgtoolerr_t dsk_image_init_pc99_mfm(imgtool_image *image, imgtool_stream *f);
static imgtoolerr_t win_image_init(imgtool_image *image, imgtool_stream *f);
static void ti99_image_exit(imgtool_image *img);
static void ti99_image_info(imgtool_image *img, char *string, size_t len);
static imgtoolerr_t dsk_image_beginenum(imgtool_imageenum *enumeration, const char *path);
static imgtoolerr_t dsk_image_nextenum(imgtool_imageenum *enumeration, imgtool_dirent *ent);
static imgtoolerr_t win_image_beginenum(imgtool_imageenum *enumeration, const char *path);
static imgtoolerr_t win_image_nextenum(imgtool_imageenum *enumeration, imgtool_dirent *ent);
static imgtoolerr_t ti99_image_freespace(imgtool_image *img, UINT64 *size);
static imgtoolerr_t ti99_image_readfile(imgtool_image *img, const char *fpath, const char *fork, imgtool_stream *destf);
static imgtoolerr_t ti99_image_writefile(imgtool_image *img, const char *fpath, const char *fork, imgtool_stream *sourcef, option_resolution *writeoptions);
static imgtoolerr_t dsk_image_deletefile(imgtool_image *img, const char *fpath);
static imgtoolerr_t win_image_deletefile(imgtool_image *img, const char *fpath);
static imgtoolerr_t dsk_image_create_mess(imgtool_image *image, imgtool_stream *f, option_resolution *createoptions);
static imgtoolerr_t dsk_image_create_v9t9(imgtool_image *image, imgtool_stream *f, option_resolution *createoptions);

enum
{
	dsk_createopts_volname = 'A',
	dsk_createopts_sides = 'B',
	dsk_createopts_tracks = 'C',
	dsk_createopts_sectors = 'D',
	dsk_createopts_protection = 'E',
	dsk_createopts_density = 'F'
};

OPTION_GUIDE_START( dsk_create_optionguide )
	OPTION_STRING(dsk_createopts_volname, "label",	"Volume name" )
	OPTION_INT(dsk_createopts_sides, "sides", "Sides" )
	OPTION_INT(dsk_createopts_tracks, "tracks", "Tracks" )
	OPTION_INT(dsk_createopts_sectors, "sectors",	"Sectors (1->9 for SD, 1->18 for DD, 1->36 for HD)" )
	OPTION_INT(dsk_createopts_protection, "protection", "Protection (0 for normal, 1 for protected)" )
	OPTION_ENUM_START(dsk_createopts_density, "density", "Density" )
		OPTION_ENUM(	0,		"Auto",				"Auto" )
		OPTION_ENUM(	1,		"SD",				"Single Density" )
		OPTION_ENUM(	2,		"DD",				"Double Density" )
		OPTION_ENUM(	3,		"HD",				"High Density" )
	OPTION_ENUM_END
OPTION_GUIDE_END

#define dsk_create_optionspecs "B1-[2];C1-[40]-80;D1-[18]-36;E[0]-1;F[0]-3"

static imgtoolerr_t ti99_createmodule_internal(imgtool_library *library, ti99_img_format img_format)
{
	imgtoolerr_t err;
	struct ImageModule *module;
	const char *identifier = NULL;

	switch (img_format)
	{
	case if_mess:
		identifier = "ti99_old";
		break;
	case if_v9t9:
		identifier = "v9t9";
		break;
	case if_pc99_fm:
		identifier = "pc99fm";
		break;
	case if_pc99_mfm:
		identifier = "pc99mfm";
		break;
	case if_harddisk:
		identifier = "ti99hd";
		break;
	}

	err = imgtool_library_createmodule(library, identifier, &module);
	if (err)
		return err;

	module->image_extra_bytes = sizeof(ti99_lvl2_imgref);
	module->imageenum_extra_bytes = sizeof(dsk_iterator);

	switch (img_format)
	{
	case if_mess:
		module->description			= "TI99 Diskette (old MESS format)";
		module->open				= dsk_image_init_mess;
		module->create				= dsk_image_create_mess;
		module->createimage_optguide= dsk_create_optionguide;
		module->createimage_optspec	= dsk_create_optionspecs;
		break;

	case if_v9t9:
		module->description			= "TI99 Diskette (V9T9 format)";
		module->open				= dsk_image_init_v9t9;
		module->create				= dsk_image_create_v9t9;
		module->createimage_optguide= dsk_create_optionguide;
		module->createimage_optspec	= dsk_create_optionspecs;
		break;

	case if_pc99_fm:
		module->description			= "TI99 Diskette (PC99 FM format)";
		module->open				= dsk_image_init_pc99_fm;
		/*module->create			= dsk_image_create_pc99fm;
		module->createimage_optguide= ...;
		module->createimage_optspec	= ...;*/
		break;

	case if_pc99_mfm:
		module->description			= "TI99 Diskette (PC99 MFM format)";
		module->open				= dsk_image_init_pc99_mfm;
		/*module->create			= dsk_image_create_pc99mfm;
		module->createimage_optguide= ...;
		module->createimage_optspec	= ...;*/
		break;

	case if_harddisk:
		module->description			= "TI99 Harddisk";
		module->open				= win_image_init;
		/*module->create			= hd_image_create;
		module->createimage_optguide= ...;
		module->createimage_optspec	= ...;*/
		break;
	}

	switch (img_format)
	{
	case if_mess:
	case if_v9t9:
	case if_pc99_fm:
	case if_pc99_mfm:
		module->extensions			= "dsk\0";
		module->begin_enum			= dsk_image_beginenum;
		module->next_enum			= dsk_image_nextenum;
		module->delete_file			= dsk_image_deletefile;
		break;

	case if_harddisk:
		module->extensions			= "hd\0";
		module->begin_enum			= win_image_beginenum;
		module->next_enum			= win_image_nextenum;
		module->delete_file			= win_image_deletefile;
		break;
	}

	module->eoln					= EOLN_CR;

	module->close					= ti99_image_exit;
	module->info					= ti99_image_info;
	module->free_space				= ti99_image_freespace;
	module->read_file				= ti99_image_readfile;
	module->write_file				= ti99_image_writefile;

	/*module->writefile_optguide		= ...;
	module->writefile_optspec		= ...;
	module->extra					= NULL;*/

	return IMGTOOLERR_SUCCESS;
}

imgtoolerr_t ti99_createmodule(imgtool_library *library)
{
	imgtoolerr_t reply;

	reply = ti99_createmodule_internal(library, if_mess);
	if (!reply)
		reply = ti99_createmodule_internal(library, if_v9t9);
	if (!reply)
		reply = ti99_createmodule_internal(library, if_pc99_fm);
	if (!reply)
		reply = ti99_createmodule_internal(library, if_pc99_mfm);
	if (!reply)
		reply = ti99_createmodule_internal(library, if_harddisk);

	return reply;
}

/*
	Open a file as a ti99_image (common code).
*/
static int dsk_image_init(imgtool_image *img, imgtool_stream *f, ti99_img_format img_format)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	dsk_vib vib;
	int reply;
	int totphysrecs;
	unsigned fdir_aphysrec;
	int i;

	/* open disk image at level 1 */
	reply = open_image_lvl1(f, img_format, &image->l1_img, &vib);
	if (reply)
		return reply;

	/* open disk image at level 2 */
	image->type = L2I_DSK;

	/* first compute AU size and number of AUs */
	totphysrecs = get_UINT16BE(vib.totphysrecs);

	image->AUformat.physrecsperAU = (totphysrecs + 1599) / 1600;
	/* round to next larger power of 2 */
	for (i = 1; i < image->AUformat.physrecsperAU; i <<= 1)
		;
	image->AUformat.physrecsperAU = i;
	image->AUformat.totAUs = totphysrecs / image->AUformat.physrecsperAU;

	/* extract number of physrecs */
	image->u.dsk.totphysrecs = get_UINT16BE(vib.totphysrecs);

	/* read and check main volume catalog */
	reply = dsk_read_catalog(image, 1, &image->u.dsk.catalogs[0]);
	if (reply)
		return reply;

	image->u.dsk.fdir_aphysrec[0] = 1;

	/* read and check subdirectory catalogs */
	/* Note that the reserved areas used for HFDC subdirs may be used for other
	purposes by other FDRs, so, if we get any error, we will assume there is no
	subdir after all... */
	image->u.dsk.catalogs[0].num_subdirs = 0;
	for (i=0; i<3; i++)
	{
		fdir_aphysrec = get_UINT16BE(vib.subdir[i].fdir_aphysrec);
		if ((! memcmp(vib.subdir[i].name, "\0\0\0\0\0\0\0\0\0\0", 10))
				|| (! memcmp(vib.subdir[i].name, "          ", 10)))
		{
			/* name is empty: fine with us unless there is a fdir pointer */
			if (fdir_aphysrec != 0)
			{
				image->u.dsk.catalogs[0].num_subdirs = 0;
				break;
			}
		}
		else if (check_fname(vib.subdir[i].name))
		{
			/* name is invalid: this is not an HFDC format floppy */
			image->u.dsk.catalogs[0].num_subdirs = 0;
			break;
		}
		else
		{
			/* there is a non-empty name */
			if ((fdir_aphysrec == 0) || (fdir_aphysrec >= totphysrecs))
			{
				/* error: fdir pointer is invalid or NULL */
				image->u.dsk.catalogs[0].num_subdirs = 0;
				break;
			}
			/* fill in descriptor fields */
			image->u.dsk.fdir_aphysrec[image->u.dsk.catalogs[0].num_subdirs+1] = fdir_aphysrec;
			/*image->u.dsk.catalogs[0].subdirs[image->u.dsk.catalogs[0].num_subdirs].dir_ptr = fdir_aphysrec;*/
			memcpy(image->u.dsk.catalogs[0].subdirs[image->u.dsk.catalogs[0].num_subdirs].name, vib.subdir[i].name, 10);
			reply = dsk_read_catalog(image, fdir_aphysrec, &image->u.dsk.catalogs[image->u.dsk.catalogs[0].num_subdirs+1]);
			if (reply)
			{
				/* error: invalid fdir */
				image->u.dsk.catalogs[0].num_subdirs = 0;
				break;
			}
			/* found valid subdirectory: increment subdir count */
			image->u.dsk.catalogs[0].num_subdirs++;
		}
	}

	/* extract volume name */
	memcpy(image->vol_name, vib.name, 10);

	/* initialize default data_offset */
	image->data_offset = 32+2;

	return 0;
}

/*
	Open a file as a ti99_image (MESS format).
*/
static imgtoolerr_t dsk_image_init_mess(imgtool_image *image, imgtool_stream *f)
{
	return dsk_image_init(image, f, if_mess);
}

/*
	Open a file as a ti99_image (V9T9 format).
*/
static imgtoolerr_t dsk_image_init_v9t9(imgtool_image *image, imgtool_stream *f)
{
	return dsk_image_init(image, f, if_v9t9);
}

/*
	Open a file as a ti99_image (PC99 FM format).
*/
static imgtoolerr_t dsk_image_init_pc99_fm(imgtool_image *image, imgtool_stream *f)
{
	return dsk_image_init(image, f, if_pc99_fm);
}

/*
	Open a file as a ti99_image (PC99 MFM format).
*/
static imgtoolerr_t dsk_image_init_pc99_mfm(imgtool_image *image, imgtool_stream *f)
{
	return dsk_image_init(image, f, if_pc99_mfm);
}

/*
	Open a file as a ti99_image (harddisk format).
*/
static imgtoolerr_t win_image_init(imgtool_image *img, imgtool_stream *f)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	win_vib_ddr vib;
	int reply;
	int i;

	/* open disk image at level 1 */
	reply = open_image_lvl1(f, if_harddisk, & image->l1_img, NULL);
	if (reply)
		return reply;

	/* open disk image at level 2 */
	image->type = L2I_WIN;

	/* read VIB */
	reply = read_absolute_physrec(&image->l1_img, 0, &vib);
	if (reply)
		return reply;

	/* guess VIB version */
	image->u.win.vib_version = memcmp(vib.u.vib_v1.id, "WIN", 3) ? win_vib_v2 : win_vib_v1;

	/* extract AU size and number of AUs */
	image->AUformat.physrecsperAU = ((get_UINT16BE(vib.params) >> 12) & 0xf) + 1;
	image->AUformat.totAUs = get_UINT16BE(vib.totAUs);

	/* extract volume name */
	memcpy(image->vol_name, vib.name, 10);

	/* extract data_offset */
	switch (image->u.win.vib_version)
	{
	case win_vib_v1:
		image->data_offset = 64;
		break;

	case win_vib_v2:
		image->data_offset = vib.u.vib_v2.res_AUs * 64;
		break;
	}

	/* read allocation bitmap (aphysrecs 1 through n, n<=33) */
	for (i=0; i < (image->AUformat.totAUs+2047)/2048; i++)
	{
		reply = read_absolute_physrec(&image->l1_img, i+1, image->abm+i*256);
		if (reply)
			return reply;
	}

	return 0;
}

/*
	close a ti99_image
*/
static void ti99_image_exit(imgtool_image *img)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);

	close_image_lvl1(&image->l1_img);
}

/*
	get basic information on a ti99_image

	Currently returns the volume name
*/
static void ti99_image_info(imgtool_image *img, char *string, size_t len)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	char vol_name[11];

	fname_to_str(vol_name, image->vol_name, 11);

	snprintf(string, len, "%s", vol_name);
}

/*
	Open the disk catalog for enumeration 
*/
static imgtoolerr_t dsk_image_beginenum(imgtool_imageenum *enumeration, const char *path)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img_enum_image(enumeration));
	dsk_iterator *iter = (dsk_iterator *) img_enum_extrabytes(enumeration);

	iter->image = image;
	iter->level = 0;
	iter->listing_subdirs = 1;
	iter->index[0] = 0;
	iter->cur_catalog = &iter->image->u.dsk.catalogs[0];

	return 0;
}

/*
	Enumerate disk catalog next entry
*/
static imgtoolerr_t dsk_image_nextenum(imgtool_imageenum *enumeration, imgtool_dirent *ent)
{
	dsk_iterator *iter = (dsk_iterator*) img_enum_extrabytes(enumeration);
	dsk_fdr fdr;
	int reply;
	unsigned fdr_aphysrec;


	ent->corrupt = 0;
	ent->eof = 0;

	/* iterate through catalogs to next file or dir entry */
	while ((iter->level >= 0)
			&& (iter->index[iter->level] >= (iter->listing_subdirs
												? iter->cur_catalog->num_subdirs
												: iter->cur_catalog->num_files)))
	{
		if (iter->listing_subdirs)
		{
			iter->listing_subdirs = 0;
			iter->index[iter->level] = 0;
		}
		else
		{
			iter->listing_subdirs = 1;
			if (! iter->level)
				iter->level = -1;
			else
			{
				iter->level = 0;
				iter->index[0]++;
				iter->cur_catalog = &iter->image->u.dsk.catalogs[0];
			}
		}
	}

	if (iter->level < 0)
	{
		ent->eof = 1;
	}
	else
	{
		if (iter->listing_subdirs)
		{
			fname_to_str(ent->filename, iter->image->u.dsk.catalogs[0].subdirs[iter->index[iter->level]].name, sizeof(ent->filename) / sizeof(ent->filename[0]));

			/* set type of DIR */
			snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "DIR");

			/* len in physrecs */
			ent->filesize = 1;

			/* recurse subdirectory */
			iter->listing_subdirs = 0;	/* no need to list subdirs as only the
										root dir has subdirs in DSK format */
			iter->level = 1;
			iter->cur_catalog = &iter->image->u.dsk.catalogs[iter->index[0]+1];
			iter->index[iter->level] = 0;
		}
		else
		{
			fdr_aphysrec = iter->cur_catalog->files[iter->index[iter->level]].fdr_ptr;
			reply = read_absolute_physrec(& iter->image->l1_img, fdr_aphysrec, & fdr);
			if (reply)
				return IMGTOOLERR_READERROR;
#if 0
			fname_to_str(ent->filename, fdr.name, sizeof(ent->filename) / sizeof(ent->filename[0]));
#else
			{
				char buf[11];

				ent->filename[0] = '\0';
				if (iter->level)
				{
					fname_to_str(ent->filename, iter->image->u.dsk.catalogs[0].subdirs[iter->index[0]].name, sizeof(ent->filename) / sizeof(ent->filename[0]));
					strncat(ent->filename, ".", sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
				}
				fname_to_str(buf, fdr.name, 11);
				strncat(ent->filename, buf, sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
			}
#endif
			/* parse flags */
			if (fdr.flags & fdr99_f_program)
				snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "PGM%s",
							(fdr.flags & fdr99_f_wp) ? " R/O" : "");
			else
				snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "%c/%c %d%s",
							(fdr.flags & fdr99_f_int) ? 'I' : 'D',
							(fdr.flags & fdr99_f_var) ? 'V' : 'F',
							fdr.reclen,
							(fdr.flags & fdr99_f_wp) ? " R/O" : "");
			/* len in physrecs */
			ent->filesize = get_UINT16BE(fdr.fphysrecs);

			iter->index[iter->level]++;
		}
	}

	return 0;
}

/*
	Open the disk catalog for enumeration 
*/
static imgtoolerr_t win_image_beginenum(imgtool_imageenum *enumeration, const char *path)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img_enum_image(enumeration));
	win_iterator *iter = (win_iterator *) img_enum_extrabytes(enumeration);
	imgtoolerr_t errorcode;

	iter->image = image;
	iter->level = 0;
	iter->listing_subdirs = 1;
	iter->index[0] = 0;
	errorcode = win_read_catalog(image, 0, &iter->catalog[0]);
	if (errorcode)
		return errorcode;

	return 0;
}

/*
	Enumerate disk catalog next entry
*/
static imgtoolerr_t win_image_nextenum(imgtool_imageenum *enumeration, imgtool_dirent *ent)
{
	win_iterator *iter = (win_iterator *) img_enum_extrabytes(enumeration);
	unsigned fdr_aphysrec;
	win_fdr fdr;
	int reply;
	int i;


	ent->corrupt = 0;
	ent->eof = 0;

	/* iterate through catalogs to next file or dir entry */
	while ((iter->level >= 0)
			&& (iter->index[iter->level] >= (iter->listing_subdirs
												? iter->catalog[iter->level].num_subdirs
												: iter->catalog[iter->level].num_files)))
	{
		if (iter->listing_subdirs)
		{
			iter->listing_subdirs = 0;
			iter->index[iter->level] = 0;
		}
		else
		{
			iter->listing_subdirs = 1;
			iter->level--;
			iter->index[iter->level]++;
		}
	}

	if (iter->level < 0)
	{
		ent->eof = 1;
	}
	else
	{
		if (iter->listing_subdirs)
		{
#if 0
			fname_to_str(ent->filename, iter->catalog[iter->level].subdirs[iter->index[iter->level]].name, sizeof(ent->filename) / sizeof(ent->filename[0]));
#else
			{
				char buf[11];

				ent->filename[0] = '\0';
				for (i=0; i<iter->level; i++)
				{
					fname_to_str(buf, iter->catalog[i].subdirs[iter->index[i]].name, 11);
					strncat(ent->filename, buf, sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
					strncat(ent->filename, ".", sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
				}
				fname_to_str(buf, iter->catalog[iter->level].subdirs[iter->index[iter->level]].name, 11);
				strncat(ent->filename, buf, sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
			}
#endif

			/* set type of DIR */
			snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "DIR");

			/* len in physrecs */
			ent->filesize = 2;

			/* recurse subdirectory */
			/*iter->listing_subdirs = 1;*/
			iter->level++;
			iter->index[iter->level] = 0;
			reply = win_read_catalog(iter->image, iter->catalog[iter->level-1].subdirs[iter->index[iter->level-1]].dir_ptr, &iter->catalog[iter->level]);
			if (reply)
			{
				ent->corrupt = 1;
				return reply;
			}
		}
		else
		{
			fdr_aphysrec = iter->catalog[iter->level].files[iter->index[iter->level]].fdr_ptr*iter->image->AUformat.physrecsperAU;
			reply = read_absolute_physrec(& iter->image->l1_img, fdr_aphysrec, & fdr);
			if (reply)
				return IMGTOOLERR_READERROR;
#if 0
			fname_to_str(ent->filename, iter->catalog[iter->level].files[iter->index[iter->level]].name, sizeof(ent->filename) / sizeof(ent->filename[0]));
#else
			{
				char buf[11];

				ent->filename[0] = '\0';
				for (i=0; i<iter->level; i++)
				{
					fname_to_str(buf, iter->catalog[i].subdirs[iter->index[i]].name, 11);
					strncat(ent->filename, buf, sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
					strncat(ent->filename, ".", sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
				}
				fname_to_str(buf, iter->catalog[iter->level].files[iter->index[iter->level]].name, 11);
				strncat(ent->filename, buf, sizeof(ent->filename) / sizeof(ent->filename[0]) - 1);
			}
#endif
			/* parse flags */
			if (fdr.flags & fdr99_f_program)
				snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "PGM%s",
							(fdr.flags & fdr99_f_wp) ? " R/O" : "");
			else
				snprintf(ent->attr, sizeof(ent->attr) / sizeof(ent->attr[0]), "%c/%c %d%s",
							(fdr.flags & fdr99_f_int) ? 'I' : 'D',
							(fdr.flags & fdr99_f_var) ? 'V' : 'F',
							fdr.reclen,
							(fdr.flags & fdr99_f_wp) ? " R/O" : "");
			/* len in physrecs */
			ent->filesize = get_win_fdr_fphysrecs(&fdr);

			iter->index[iter->level]++;
		}
	}

	return 0;
}

/*
	Compute free space on disk image (in AUs)
*/
static imgtoolerr_t ti99_image_freespace(imgtool_image *img, UINT64 *size)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	size_t freeAUs;
	int i;

	freeAUs = 0;
	for (i=0; i<image->AUformat.totAUs; i++)
	{
		if (! (image->abm[i >> 3] & (1 << (i & 7))))
			freeAUs++;
	}

	*size = freeAUs;

	return IMGTOOLERR_SUCCESS;
}

/*
	Extract a file from a ti99_image.  The file is saved in tifile format.
*/
static imgtoolerr_t ti99_image_readfile(imgtool_image *img, const char *fpath, const char *fork, imgtool_stream *destf)
{
#if 1

	/* extract data as TIFILES */
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	ti99_lvl2_fileref src_file;
	ti99_lvl2_fileref dst_file;
	ti99_date_time date_time;
	int fphysrecs;
	int i;
	UINT8 buf[256];
	imgtoolerr_t errorcode;


	if (check_fpath(fpath))
		return IMGTOOLERR_BADFILENAME;

	/* open file on TI image */
	switch (image->type)
	{
	case L2I_DSK:
		errorcode = open_file_lvl2_dsk(image, fpath, &src_file);
		break;

	case L2I_WIN:
		errorcode = open_file_lvl2_win(image, fpath, &src_file);
		break;

	default:
		errorcode = -1;
		break;
	}
	if (errorcode)
		return errorcode;

	errorcode = new_file_lvl2_tifiles(destf, &dst_file);
	if (errorcode)
		return errorcode;

	/* write TIFILE header */
	/* set up parameters */
	set_file_flags(&dst_file, get_file_flags(&src_file));
	set_file_recsperphysrec(&dst_file, get_file_recsperphysrec(&src_file));
	errorcode = set_file_fphysrecs(&dst_file, get_file_fphysrecs(&src_file));
	if (errorcode)
		return errorcode;
	set_file_eof(&dst_file, get_file_eof(&src_file));
	errorcode = set_file_reclen(&dst_file, get_file_reclen(&src_file));
	if (errorcode)
		return errorcode;
	errorcode = set_file_fixrecs(&dst_file, get_file_fixrecs(&src_file));
	if (errorcode)
		return errorcode;

	get_file_creation_date(&src_file, &date_time);
	/*if ((date_time.time_MSB == 0) || (date_time.time_LSB == 0)
			|| (date_time.date_MSB == 0) || (date_time.date_LSB == 0))
		current_date_time(&date_time);*/
	set_file_creation_date(&dst_file, date_time);

	get_file_update_date(&src_file, &date_time);
	/*if ((date_time.time_MSB == 0) || (date_time.time_LSB == 0)
			|| (date_time.date_MSB == 0) || (date_time.date_LSB == 0))
		current_date_time(&date_time);*/
	set_file_update_date(&dst_file, date_time);

	if (stream_write(destf, & dst_file.u.tifiles.hdr, 128) != 128)
		return IMGTOOLERR_WRITEERROR;

	/* copy data to TIFILE */
	fphysrecs = get_file_fphysrecs(&src_file);

	for (i=0; i<fphysrecs; i++)
	{
		errorcode = read_file_physrec(& src_file, i, buf);
		if (errorcode)
			return errorcode;

		errorcode = write_file_physrec(& dst_file, i, buf);
		if (errorcode)
			return errorcode;
	}

	return 0;

#else

	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	ti99_lvl3_fileref src_file;
	UINT8 buf[256];
	int reclen;
	char lineend = '\r';
	int errorcode;


	if (check_fpath(fpath))
		return IMGTOOLERR_BADFILENAME;

	/* open file on TI image */
	switch (image->type)
	{
	case L2I_DSK:
		errorcode = open_file_lvl2_dsk(image, fpath, &src_file.l2_file);
		break;

	case L2I_WIN:
		errorcode = open_file_lvl2_win(image, fpath, &src_file.l2_file);
		break;
	}
	if (errorcode)
		return errorcode;

	errorcode = open_file_lvl3(& src_file);
	if (errorcode)
		return errorcode;

	/* write text data */
	while (! is_eof(& src_file))
	{
		errorcode = read_next_record(& src_file, buf, & reclen);
		if (errorcode)
			return errorcode;
		if (stream_write(destf, buf, reclen) != reclen)
			return IMGTOOLERR_WRITEERROR;
		if (stream_write(destf, &lineend, 1) != 1)
			return IMGTOOLERR_WRITEERROR;
	}

	return 0;

#endif
}

/*
	Add a file to a ti99_image.  The file must be in tifile format.
*/
static imgtoolerr_t ti99_image_writefile(imgtool_image *img, const char *fpath, const char *fork, imgtool_stream *sourcef, option_resolution *writeoptions)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	const char *filename;
	char ti_fname[10];
	ti99_lvl2_fileref src_file;
	ti99_lvl2_fileref dst_file;
	ti99_date_time date_time;
	int i;
	int fphysrecs;
	UINT8 buf[256];
	imgtoolerr_t errorcode;
	int parent_ref_valid, parent_ref = 0;
	ti99_catalog *catalog, catalog_buf = {0, };


	(void) writeoptions;

	if (check_fpath(fpath))
		return IMGTOOLERR_BADFILENAME;

	switch (image->type)
	{
	case L2I_DSK:
		errorcode = dsk_find_catalog_entry(image, fpath, &parent_ref_valid, &parent_ref, NULL, NULL);
		if (errorcode == 0)
			/* file already exists: causes an error for now */
			return IMGTOOLERR_UNEXPECTED;
		else if ((! parent_ref_valid) || (errorcode != IMGTOOLERR_FILENOTFOUND))
			return errorcode;
		break;

	case L2I_WIN:
		errorcode = win_find_catalog_entry(image, fpath, &parent_ref_valid, &parent_ref, &catalog_buf, NULL, NULL);
		if (errorcode == 0)
			/* file already exists: causes an error for now */
			return IMGTOOLERR_UNEXPECTED;
		else if ((! parent_ref_valid) || (errorcode != IMGTOOLERR_FILENOTFOUND))
			return errorcode;
		break;
	}

	errorcode = open_file_lvl2_tifiles(sourcef, & src_file);
	if (errorcode)
		return errorcode;

	/* create new file */
	filename = strrchr(fpath, '.');
	if (filename)
		filename++;
	else
		filename = fpath;
	str_to_fname(ti_fname, filename);
	switch (image->type)
	{
	case L2I_DSK:
		errorcode = new_file_lvl2_dsk(image, parent_ref, ti_fname, &dst_file);
		if (errorcode)
			return errorcode;
		break;

	case L2I_WIN:
		errorcode = new_file_lvl2_win(image, &catalog_buf, ti_fname, &dst_file);
		if (errorcode)
			return errorcode;
		break;
	}

	/* set up parameters */
	set_file_flags(&dst_file, get_file_flags(&src_file));
	set_file_recsperphysrec(&dst_file, get_file_recsperphysrec(&src_file));
	errorcode = set_file_fphysrecs(&dst_file, /*get_file_fphysrecs(&src_file)*/0);
	if (errorcode)
		return errorcode;
	set_file_eof(&dst_file, get_file_eof(&src_file));
	errorcode = set_file_reclen(&dst_file, get_file_reclen(&src_file));
	if (errorcode)
		return errorcode;
	errorcode = set_file_fixrecs(&dst_file, get_file_fixrecs(&src_file));
	if (errorcode)
		return errorcode;

	get_file_creation_date(&src_file, &date_time);
	/*if ((date_time.time_MSB == 0) || (date_time.time_LSB == 0)
			|| (date_time.date_MSB == 0) || (date_time.date_LSB == 0))
		current_date_time(&date_time);*/
	set_file_creation_date(&dst_file, date_time);

	get_file_update_date(&src_file, &date_time);
	/*if ((date_time.time_MSB == 0) || (date_time.time_LSB == 0)
			|| (date_time.date_MSB == 0) || (date_time.date_LSB == 0))
		current_date_time(&date_time);*/
	set_file_update_date(&dst_file, date_time);

	/* alloc data physrecs */
	fphysrecs = get_file_fphysrecs(&src_file);
	switch (dst_file.type)
	{
	case L2F_DSK:
		errorcode = dsk_alloc_file_physrecs(&dst_file.u.dsk, fphysrecs);
		if (errorcode)
			return errorcode;
		break;

	case L2F_WIN:
		errorcode = win_alloc_file_physrecs(&dst_file.u.win, fphysrecs);
		if (errorcode)
			return errorcode;
		break;

	case L2F_TIFILES:
		break;
	}

	/* copy data */
	for (i=0; i<fphysrecs; i++)
	{
		if (stream_read(sourcef, buf, 256) != 256)
			return IMGTOOLERR_READERROR;

		errorcode = write_file_physrec(& dst_file, i, buf);
		if (errorcode)
			return errorcode;
	}

	/* write fdr */
	switch (image->type)
	{
	case L2I_DSK:
		if (write_absolute_physrec(& image->l1_img, dst_file.u.dsk.fdr_aphysrec, &dst_file.u.dsk.fdr))
			return IMGTOOLERR_WRITEERROR;
		break;

	case L2I_WIN:
		/* save fphysrecs field as well */
		if (dst_file.u.win.curfdr_aphysrec == dst_file.u.win.eldestfdr_aphysrec)
			set_win_fdr_fphysrecs(&dst_file.u.win.curfdr, dst_file.u.win.fphysrecs);
		if (write_absolute_physrec(& image->l1_img, dst_file.u.win.curfdr_aphysrec, &dst_file.u.win.curfdr))
			return IMGTOOLERR_WRITEERROR;
		if (dst_file.u.win.curfdr_aphysrec != dst_file.u.win.eldestfdr_aphysrec)
		{
			dst_file.u.win.curfdr_aphysrec = dst_file.u.win.eldestfdr_aphysrec;
			if (read_absolute_physrec(& image->l1_img, dst_file.u.win.curfdr_aphysrec, &dst_file.u.win.curfdr))
				return IMGTOOLERR_WRITEERROR;
			set_win_fdr_fphysrecs(&dst_file.u.win.curfdr, dst_file.u.win.fphysrecs);
			if (write_absolute_physrec(& image->l1_img, dst_file.u.win.curfdr_aphysrec, &dst_file.u.win.curfdr))
				return IMGTOOLERR_WRITEERROR;
		}
		break;
	}

	/* update catalog */
	switch (image->type)
	{
	case L2I_DSK:
		catalog = &image->u.dsk.catalogs[parent_ref];
		for (i=0; i<128; i++)
		{
			buf[2*i] = catalog->files[i].fdr_ptr >> 8;
			buf[2*i+1] = catalog->files[i].fdr_ptr & 0xff;
		}
		if (write_absolute_physrec(& image->l1_img, image->u.dsk.fdir_aphysrec[parent_ref], buf))
			return IMGTOOLERR_WRITEERROR;
		break;

	case L2I_WIN:
		{
			win_vib_ddr parent_ddr;
			int fdir_AU;

			/* update VIB/DDR and get FDIR AU address */
			if (read_absolute_physrec(& image->l1_img, parent_ref * image->AUformat.physrecsperAU, &parent_ddr))
				return IMGTOOLERR_READERROR;
			parent_ddr.num_files = catalog_buf.num_files;
			if (write_absolute_physrec(& image->l1_img, parent_ref * image->AUformat.physrecsperAU, &parent_ddr))
				return IMGTOOLERR_WRITEERROR;
			fdir_AU = get_UINT16BE(parent_ddr.fdir_AU);

			/* generate FDIR and save it */
			for (i=0; i<127; i++)
			{
				buf[2*i] = catalog_buf.files[i].fdr_ptr >> 8;
				buf[2*i+1] = catalog_buf.files[i].fdr_ptr & 0xff;
			}
			buf[254] = parent_ref >> 8;
			buf[255] = parent_ref & 0xff;
			if (write_absolute_physrec(& image->l1_img, fdir_AU * image->AUformat.physrecsperAU, buf))
				return IMGTOOLERR_WRITEERROR;
		}
		break;
	}

	/* update bitmap */
	switch (image->type)
	{
	case L2I_DSK:
		{
			dsk_vib vib;

			if (read_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_READERROR;
			memcpy(vib.abm, image->abm, 200);
			if (write_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_WRITEERROR;
		}
		break;

	case L2I_WIN:
		/* save allocation bitmap (aphysrecs 1 through n, n<=33) */
		for (i=0; i < (image->AUformat.totAUs+2047)/2048; i++)
			if (write_absolute_physrec(&image->l1_img, i+1, image->abm+i*256))
				return IMGTOOLERR_WRITEERROR;
		break;
	}

	return 0;
}

/*
	Delete a file from a ti99_image.
*/
static imgtoolerr_t dsk_image_deletefile(imgtool_image *img, const char *fpath)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	dsk_fdr fdr;
	int i, cluster_index;
	unsigned cur_AU, cluster_lastfphysrec;
	int fphysrecs;
	int parent_ref, is_dir, catalog_index;
	imgtoolerr_t errorcode;
	UINT8 buf[256];
	ti99_catalog *catalog;


	if (check_fpath(fpath))
		return IMGTOOLERR_BADFILENAME;

	errorcode = dsk_find_catalog_entry(image, fpath, NULL, &parent_ref, &is_dir, &catalog_index);
	if (errorcode)
		return errorcode;

	if (is_dir)
	{
		catalog = &image->u.dsk.catalogs[catalog_index+1];

		if ((catalog->num_files != 0) || (catalog->num_subdirs != 0))
			return IMGTOOLERR_UNIMPLEMENTED;

		catalog = &image->u.dsk.catalogs[0];

		/* free fdir AU */
		cur_AU = image->u.dsk.fdir_aphysrec[catalog_index+1] / image->AUformat.physrecsperAU;
		image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));

		/* delete catalog entry */
		for (i=catalog_index; i<2; i++)
		{
			catalog->subdirs[i] = catalog->subdirs[i+1];
			image->u.dsk.fdir_aphysrec[i+1] = image->u.dsk.fdir_aphysrec[i+2];
		}
		memset(catalog->subdirs[2].name, 0, 10);
		catalog->subdirs[2].dir_ptr = 0;
		image->u.dsk.fdir_aphysrec[3] = 0;
		catalog->num_subdirs--;

		/* update directory and bitmap in vib */
		{
			dsk_vib vib;

			if (read_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_READERROR;

			for (i=0; i<3; i++)
			{
				memcpy(vib.subdir[i].name, catalog->subdirs[i].name, 10);
				set_UINT16BE(&vib.subdir[i].fdir_aphysrec, image->u.dsk.fdir_aphysrec[i+1]);
			}

			memcpy(vib.abm, image->abm, 200);

			if (write_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_WRITEERROR;
		}
	}
	else
	{
		catalog = &image->u.dsk.catalogs[parent_ref];

		if (read_absolute_physrec(& image->l1_img, catalog->files[catalog_index].fdr_ptr, &fdr))
			return IMGTOOLERR_READERROR;

		/* free data AUs */
		fphysrecs = get_UINT16BE(fdr.fphysrecs);

		i = 0;
		cluster_index = 0;
		while (cluster_index < 76)
		{
			cur_AU = get_dsk_fdr_cluster_baseAU(image, & fdr, cluster_index);
			if (cur_AU == 0)
				/* end of cluster list */
				break;
			cluster_lastfphysrec = get_dsk_fdr_cluster_lastfphysrec(& fdr, cluster_index);

			while (i<=cluster_lastfphysrec)
			{
				/* the condition below is an error, but it should not prevent
				us from deleting the file */
				if (cur_AU >= image->AUformat.totAUs)
					/*return IMGTOOLERR_CORRUPTIMAGE;*/
					break;

				image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));

				i += image->AUformat.physrecsperAU;
				cur_AU++;
			}

			cluster_index++;
		}
		/* the condition below is an error, but it should not prevent us from
		deleting the file */
		/*if (i<fphysrecs)
			return IMGTOOLERR_CORRUPTIMAGE;*/

		/* free fdr AU */
		cur_AU = catalog->files[catalog_index].fdr_ptr / image->AUformat.physrecsperAU;
		image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));

		/* delete catalog entry */
		for (i=catalog_index; i<127; i++)
			catalog->files[i] = catalog->files[i+1];
		catalog->files[127].fdr_ptr = 0;
		catalog->num_files--;

		/* update parent fdir */
		for (i=0; i<128; i++)
		{
			buf[2*i] = catalog->files[i].fdr_ptr >> 8;
			buf[2*i+1] = catalog->files[i].fdr_ptr & 0xff;
		}
		if (write_absolute_physrec(& image->l1_img, image->u.dsk.fdir_aphysrec[parent_ref], buf))
			return IMGTOOLERR_WRITEERROR;

		/* update bitmap */
		{
			dsk_vib vib;

			if (read_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_READERROR;
			memcpy(vib.abm, image->abm, 200);
			if (write_absolute_physrec(& image->l1_img, 0, &vib))
				return IMGTOOLERR_WRITEERROR;
		}
	}

	return 0;
}

static imgtoolerr_t win_image_deletefile(imgtool_image *img, const char *fpath)
{
	ti99_lvl2_imgref *image = (ti99_lvl2_imgref *) img_extrabytes(img);
	int parent_ddr_AU, is_dir, catalog_index;
	win_fdr fdr;
	int i;
	unsigned cur_AU, end_AU;
	unsigned curfdr_aphysrec;
	unsigned cursibFDR_index, endsibFDR_index = 0;
	int errorcode;
	UINT8 buf[256];
	ti99_catalog catalog;


	if (check_fpath(fpath))
		return IMGTOOLERR_BADFILENAME;

	errorcode = win_find_catalog_entry(image, fpath, NULL, &parent_ddr_AU, &catalog, &is_dir, &catalog_index);
	if (errorcode)
		return errorcode;

	if (is_dir)
	{
		unsigned DDR_AU;
		win_vib_ddr ddr_buf;

		/* Read DDR record */
		DDR_AU = catalog.subdirs[catalog_index].dir_ptr;
		if (read_absolute_physrec(& image->l1_img, DDR_AU*image->AUformat.physrecsperAU, &ddr_buf))
			return IMGTOOLERR_READERROR;

		/* read FDIR AU pointer */
		cur_AU = get_UINT16BE(ddr_buf.fdir_AU);

		/* sanity checks */
		if ((ddr_buf.num_files > 127) || (ddr_buf.num_subdirs > 114) || (cur_AU > image->AUformat.totAUs))
			return IMGTOOLERR_CORRUPTIMAGE;

		if ((ddr_buf.num_files != 0) || (ddr_buf.num_subdirs != 0))
			return IMGTOOLERR_UNIMPLEMENTED;

		/* free fdir AU */
		image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));

		/* free ddr AU */
		image->abm[DDR_AU >> 3] &= ~ (1 << (DDR_AU & 7));

		/* delete parent catalog entry */
		for (i=catalog_index; i<113; i++)
			catalog.subdirs[i] = catalog.subdirs[i+1];
		catalog.subdirs[114].dir_ptr = 0;
		catalog.num_subdirs--;

		/* update parent VIB/DDR */
		if (read_absolute_physrec(& image->l1_img, parent_ddr_AU * image->AUformat.physrecsperAU, &ddr_buf))
			return IMGTOOLERR_READERROR;
		ddr_buf.num_subdirs = catalog.num_subdirs;
		for (i=0; i<114; i++)
			set_UINT16BE(&ddr_buf.subdir_AU[i], catalog.subdirs[i].dir_ptr);
		if (write_absolute_physrec(& image->l1_img, parent_ddr_AU * image->AUformat.physrecsperAU, &ddr_buf))
			return IMGTOOLERR_WRITEERROR;

		/* save allocation bitmap (aphysrecs 1 through n, n<=33) */
		for (i=0; i < (image->AUformat.totAUs+2047)/2048; i++)
			if (write_absolute_physrec(&image->l1_img, i+1, image->abm+i*256))
				return IMGTOOLERR_WRITEERROR;
	}
	else
	{
		/* check integrity of FDR sibling chain, and go to last sibling */
		/* note that as we check that the back chain is consistent with the forward
		chain, we will also detect any cycle in the sibling chain, so we do not
		need to check against them explicitely */
		{
			int pastendoflist_flag;
			unsigned prevfdr_aphysrec;


			pastendoflist_flag = 0;
			cursibFDR_index = 0;
			curfdr_aphysrec = catalog.files[catalog_index].fdr_ptr * image->AUformat.physrecsperAU;
			if (read_absolute_physrec(& image->l1_img, curfdr_aphysrec, &fdr))
				return IMGTOOLERR_READERROR;

			if (get_UINT16BE(fdr.prevsibFDR_AU) != 0)
				return IMGTOOLERR_CORRUPTIMAGE;

			while (1)
			{
				if (! pastendoflist_flag)
				{
					/* look for end of list */
					for (i=0; i<54; i++)
					{
						if (get_UINT16BE(fdr.clusters[i][0]) == 0)
						{
							endsibFDR_index = cursibFDR_index;
							pastendoflist_flag = TRUE;
							break;
						}
					}
				}

				/* exit loop if end of sibling chain */
				if (! get_UINT16BE(fdr.nextsibFDR_AU))
					break;

				/* otherwise read next FDR */
				if (get_UINT16BE(fdr.nextsibFDR_AU) >= image->AUformat.totAUs)
					return IMGTOOLERR_CORRUPTIMAGE;

				prevfdr_aphysrec = curfdr_aphysrec;
				curfdr_aphysrec = get_win_fdr_nextsibFDR_aphysrec(image, &fdr);
				if (read_absolute_physrec(& image->l1_img, curfdr_aphysrec, &fdr))
					return IMGTOOLERR_READERROR;
				cursibFDR_index++;

				/* check that back chaining is consistent with forward chaining */
				if (get_win_fdr_prevsibFDR_aphysrec(image, &fdr) != prevfdr_aphysrec)
					return IMGTOOLERR_CORRUPTIMAGE;
			}
			if (! pastendoflist_flag)
				endsibFDR_index = cursibFDR_index;
		}


		while (1)
		{
			if (cursibFDR_index <= endsibFDR_index)
			{

				for (i = 0; i < 54; i++)
				{
					cur_AU = get_UINT16BE(fdr.clusters[i][0]);
					if (cur_AU == 0)
						/* end of cluster list */
						break;
					end_AU = get_UINT16BE(fdr.clusters[i][1]);

					while (cur_AU<=end_AU)
					{
						/* the condition below is an error, but it should not prevent
						us from deleting the file */
						if (cur_AU >= image->AUformat.totAUs)
							/*return IMGTOOLERR_CORRUPTIMAGE;*/
							break;

						image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));

						cur_AU++;
					}
				}
			}

			/* free fdr AU if applicable */
			if ((curfdr_aphysrec % image->AUformat.physrecsperAU) == 0)
			{
				cur_AU = curfdr_aphysrec / image->AUformat.physrecsperAU;
				image->abm[cur_AU >> 3] &= ~ (1 << (cur_AU & 7));
			}

			if (cursibFDR_index == 0)
				break;
			curfdr_aphysrec = get_win_fdr_prevsibFDR_aphysrec(image, &fdr);
			if (read_absolute_physrec(& image->l1_img, curfdr_aphysrec, &fdr))
				return IMGTOOLERR_READERROR;
			cursibFDR_index--;
		}


		/* delete catalog entry */
		for (i=catalog_index; i<127; i++)
			catalog.files[i] = catalog.files[i+1];
		catalog.files[127].fdr_ptr = 0;
		catalog.num_files--;


		/* update VIB/DDR and get FDIR AU address */
		{
			win_vib_ddr parent_ddr;

			if (read_absolute_physrec(& image->l1_img, parent_ddr_AU * image->AUformat.physrecsperAU, &parent_ddr))
				return IMGTOOLERR_READERROR;
			parent_ddr.num_files = catalog.num_files;
			if (write_absolute_physrec(& image->l1_img, parent_ddr_AU * image->AUformat.physrecsperAU, &parent_ddr))
				return IMGTOOLERR_WRITEERROR;
			cur_AU = get_UINT16BE(parent_ddr.fdir_AU);
		}

		/* generate FDIR and save it */
		for (i=0; i<127; i++)
		{
			buf[2*i] = catalog.files[i].fdr_ptr >> 8;
			buf[2*i+1] = catalog.files[i].fdr_ptr & 0xff;
		}
		buf[254] = parent_ddr_AU >> 8;
		buf[255] = parent_ddr_AU & 0xff;
		if (write_absolute_physrec(& image->l1_img, cur_AU * image->AUformat.physrecsperAU, buf))
			return IMGTOOLERR_WRITEERROR;

		/* save allocation bitmap (aphysrecs 1 through n, n<=33) */
		for (i=0; i < (image->AUformat.totAUs+2047)/2048; i++)
			if (write_absolute_physrec(&image->l1_img, i+1, image->abm+i*256))
				return IMGTOOLERR_WRITEERROR;
	}

	return 0;
}

/*
	Create a blank ti99_image (common code).

	Supports MESS and V9T9 formats only
*/
static imgtoolerr_t dsk_image_create(imgtool_image *image, imgtool_stream *f, option_resolution *createoptions, ti99_img_format img_format)
{
	const char *volname;
	int density;
	ti99_lvl1_imgref l1_img;
	int protected;

	int totphysrecs, physrecsperAU, totAUs;

	dsk_vib vib;
	UINT8 empty_sec[256];

	int i;

	l1_img.img_format = img_format;
	l1_img.file_handle = f;

	/* read options */
	volname = option_resolution_lookup_string(createoptions, dsk_createopts_volname);
	l1_img.geometry.heads = option_resolution_lookup_int(createoptions, dsk_createopts_sides);
	l1_img.geometry.cylinders = option_resolution_lookup_int(createoptions, dsk_createopts_tracks);
	l1_img.geometry.secspertrack = option_resolution_lookup_int(createoptions, dsk_createopts_sectors);
	protected = option_resolution_lookup_int(createoptions, dsk_createopts_protection);
	density = option_resolution_lookup_int(createoptions, dsk_createopts_density);

	/* NPW 03-DEC-2003 - Fixes a crash if volname is NULL */
	if (!volname)
		volname = "";

	totphysrecs = l1_img.geometry.secspertrack * l1_img.geometry.cylinders * l1_img.geometry.heads;
	physrecsperAU = (totphysrecs + 1599) / 1600;
	/* round to next larger power of 2 */
	for (i = 1; i < physrecsperAU; i <<= 1)
		;
	physrecsperAU = i;
	totAUs = totphysrecs / physrecsperAU;

	/* auto-density */
	if (density == 0)
	{
		if (l1_img.geometry.secspertrack <= 9)
			density = 1;
		else if (l1_img.geometry.secspertrack <= 18)
			density = 2;
		else
			density = 3;
	}

	/* check volume name */
	if (strchr(volname, '.') || strchr(volname, ' ') || (strlen(volname) > 10))
		return /*IMGTOOLERR_BADFILENAME*/IMGTOOLERR_PARAMCORRUPT;

	/* FM disks can hold fewer sector per track than MFM disks */
	if ((density == 1) && (l1_img.geometry.secspertrack > 9))
		return IMGTOOLERR_PARAMTOOLARGE;

	/* DD disks can hold fewer sector per track than HD disks */
	if ((density == 2) && (l1_img.geometry.secspertrack > 18))
		return IMGTOOLERR_PARAMTOOLARGE;

	/* check total disk size */
	if (totphysrecs < 2)
		return IMGTOOLERR_PARAMTOOSMALL;

	/* initialize vib in aphysrec 0 */

	/* set volume name */
	str_to_fname(vib.name, volname);

	/* set every header field */
	set_UINT16BE(& vib.totphysrecs, totphysrecs);
	vib.secspertrack = l1_img.geometry.secspertrack;
	vib.id[0] = 'D';
	vib.id[1] = 'S';
	vib.id[2] = 'K';
	vib.protection = protected ? 'P' : ' ';
	vib.cylinders = l1_img.geometry.cylinders;
	vib.heads = l1_img.geometry.heads;
	vib.density = density;
	for (i=0; i<3; i++)
	{
		memset(vib.subdir[i].name, '\0', 10);
		set_UINT16BE(& vib.subdir[i].fdir_aphysrec, 0);
	}

	/* clear bitmap */
	for (i=0; i < (totAUs>>3); i++)
		vib.abm[i] = 0;

	if (totAUs & 7)
	{
		vib.abm[i] = 0xff << (totAUs & 7);
		i++;
	}

	for (; i < 200; i++)
		vib.abm[i] = 0xff;

	/* mark first 2 aphysrecs (vib and fdir) as used */
	vib.abm[0] |= (physrecsperAU == 1) ? 3 : 1;

	/* write aphysrec 0 */
	if (write_absolute_physrec(& l1_img, 0, &vib))
		return IMGTOOLERR_WRITEERROR;


	/* now clear every other physrecs, including the FDIR record */
	memset(empty_sec, 0, 256);

	for (i=1; i<totphysrecs; i++)
		if (write_absolute_physrec(& l1_img, i, empty_sec))
			return IMGTOOLERR_WRITEERROR;


	return dsk_image_init(image, f, img_format);
}

/*
	Create a blank ti99_image (MESS format).
*/
static imgtoolerr_t dsk_image_create_mess(imgtool_image *image, imgtool_stream *f, option_resolution *createoptions)
{
	return dsk_image_create(image, f, createoptions, if_mess);
}

/*
	Create a blank ti99_image (V9T9 format).
*/
static imgtoolerr_t dsk_image_create_v9t9(imgtool_image *image, imgtool_stream *f, option_resolution *createoptions)
{
	return dsk_image_create(image, f, createoptions, if_v9t9);
}
